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The Structure of H-2K^b and K^bm8 Complexed to a Herpes Simplex Virus Determinant: Evidence for a Conformational Switch That Governs T Cell Repertoire Selection and Viral Resistance^1,2

Andrew I. Webb^3,*, Natalie A. Borg^3,*, Michelle A. Dunstone^*, Lars Kjer-Nielsen, Travis Beddoe^*, James McCluskey^,, Francis R. Carbone^,, Stephen P. Bottomley^*, Marie-Isabel Aguilar^*, Anthony W. Purcell^4,5,, and Jamie Rossjohn^4,5,*

^* Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, and Department of Microbiology and Immunology, and ImmunoID, University of Melbourne, Parkville, Victoria, Australia

	Abstract

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Polymorphism within the MHC not only affects peptide specificity but also has a critical influence on the T cell repertoire; for example, the CD8 T cell response toward an immunodominant HSV glycoprotein B peptide is more diverse and of higher avidity in H-2^bm8 compared with H-2^b mice. We have examined the basis for the selection of these distinct antiviral T cell repertoires by comparing the high-resolution structures of K^b and K^bm8, in complex with cognate peptide Ag. Although K^b and K^bm8 differ by four residues within the Ag-binding cleft, the most striking difference in the two structures was the disparate conformation adopted by the shared residue, Arg⁶². The altered dynamics of Arg⁶², coupled with a small rigid-body movement in the ₁ helix encompassing this residue, correlated with biased V usage in the B6 mice. Moreover, an analysis of all known TCR/MHC complexes reveals that Arg⁶² invariably interacts with the TCR CDR1 loop. Accordingly, Arg⁶² appears to function as a conformational switch that may govern T cell selection and protective immunity.

	Introduction

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The cytotoxic T cell response toward viruses is mediated by class I MHC molecules complexed to viral peptide Ags. These complexes are expressed on the surface of infected cells and are subsequently recognized by clonally distributed TCR on CD8⁺ T lymphocytes. Appropriately armed and activated CD8⁺ T cells can eliminate infected cells and prevent viral replication. The CD8⁺ T cell response toward many viruses is extremely focused with viral eradication occurring through the recognition of only one or two immunodominant epitopes. Polymorphism in class I molecules not only diversifies selection of peptide Ags (1) but also broadens the T cell repertoire that is used to recognize pathogens. Even single amino acid differences in MHC molecules can exert profound effects on T cell repertoire selection and dictate subtle changes in peptide ligand selection (2) and Ag processing (3, 4, 38). The effect of the polymorphism may be to alter the thymic peptide repertoire and influence thymic positive and negative T cell selection, to alter the viral determinants presented during infection, or to present the same viral determinants in an altered conformation, resulting in selection of different T cell clonotypes. We have examined the CD8⁺ T cell response to infection with HSV-1 in C57BL/6 (B6) mice to study the influence of polymorphism on antiviral responses at a molecular level. The response to HSV-1 in B6 mice is almost entirely focused on a single immunodominant determinant (glycoprotein B 498–505 (SSIEFARL)), which encompasses up to 90% of the total response. Moreover, in B6 mice, SSIEFARL-specific CD8⁺ T cells exhibit TCR V (such that 70% use V2) and V usage bias (60% use V10, and 20% use V8S1) (5, 6). T cell clonotypes expressing these V and V pairings are selected from a diverse naive repertoire.

Spontaneous mutations in the H-2K molecules of B6 mice has been used as a tool to investigate the role of MHC polymorphism in the immune response and were initially identified by their ability to elicit allogeneic T cell responses in wild-type mice (7). Of particular interest in our study is the mutant molecule H-2K^bm8, which differs from K^b at four amino acids (Y22F, M23I, E24S, and D30N) that are located within the Ag-binding cleft and are inaccessible to TCRs (8). The ability of H-2^bm8 (Bm8) mice to elicit allogeneic T cell responses, therefore, most likely reflects altered peptide repertoire and/or changes in MHC-peptide conformation expressed on the allograft, consistent with recent structures of monoallelic variants and analysis of their ligand repertoires (2, 9, 10, 11, 12, 13). The response of Bm8 mice to viral and other Ags has been studied in detail. CD8⁺ T cell immunity to OVA is poor in Bm8 mice, yet this response in B6 mice is robust and dominated by the SIINFEKL determinant. This difference in response is due to poor K^bm8-restricted presentation of SIINFEKL (14, 15). In contrast, comparable immune responses and equivalent protective immunity in both strains are seen following challenge with vesicular stomatitis virus (VSV)⁶ or Sendai virus (SEV). This observation suggests that both strains produce diverse naive T cell repertoires capable of clearing pathogens using similar T cell determinants and hierarchies of immunodominance. Analysis of the structures of K^b and K^bm8 complexed to dominant peptide determinants from VSV and SEV revealed subtle conformational changes in the complexes, but these were not associated with major functional differences in the CD8⁺ T cells generated in B6 and Bm8 mice (8, 16, 17). However, it is remarkable that, although in HSV-1 infection, the SSIEFARL epitope dominates the CD8⁺ T cell response in both strains of mice, Bm8 mice are five times more resistant to lethal challenge with HSV-1 than B6 mice. This observation correlates with a more diversified repertoire and higher functional avidity of SSIEFARL-specific CD8⁺ T cells in Bm8 mice (18). The basis of this MHC-linked enhancement in antiviral resistance and T cell selection is not well understood but is thought to be related to differences in T cell selection in the two strains of mice. In this study, we investigate the structural influence of the MHC class I polymorphism between K^b and K^bm8 in the presentation and recognition of the SSIEFARL determinant and examine potential extrathymic mechanisms of clonotypic expansion based on the differences observed in the two structures.

	Materials and Methods

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Expression, purification, crystallization, and structure determination

Four amino acid substitutions differentiate H-2K^b from K^bm8. Truncated K^bm8 (aa 1–285) was generated by site-directed mutagenesis using a K^b plasmid template (QuikChange; Stratagene, La Jolla, CA). Recombinant K^b and K^bm8 molecules were expressed as inclusion bodies, refolded, and purified, as previously described (19).

All crystallization trials were conducted using the hanging-drop vapor diffusion technique (20, 21). The crystals were grown under identical conditions for each allele, by mixing equal volumes of 10 mg/ml K^b and K^bm8 peptide complexes with the reservoir buffer (0.1 M sodium cacodylate, 0.2 M calcium acetate, and 14% (w/v) polyethylene glycol 8000 (pH 6.5)) and microseeded from crystals grown in 16% (w/v) polyethylene glycol 8000 at room temperature. Crystals were frozen following a stepwise transfer from 5 to 10% of the cryoprotectant glycerol with 5 min per condition. The crystals belong to space group P2₁ with isomorphous unit cell dimensions. A 2.0- and 1.8-Å data set for K^b-HSV and K^bm8-HSV were collected, respectively, and scaled using the HKL suite of programs. The K^b- and K^bm8-HSV structures were determined by molecular replacement (using the K^b complex 1KJ3 (22) minus peptide and water molecules as the search probe). Unbiased features in the initial electron density map, including that of the SSIEFARL peptide, confirmed the correctness of the molecular replacement solution. The progress of refinement was monitored by the R_free value (4% of the data) with neither a nor a low-resolution cutoff being applied to the data. The structure was refined using rigid-body fitting of the individual domains followed by the simulated-annealing protocol implemented in CNS (version 1.0) (23), interspersed with rounds of model building using the program O (24). Tightly restrained individual B factor refinement was used, and bulk solvent corrections were applied to the data set. Water molecules were included in the model if they were within hydrogen-bonding distance to chemically reasonable groups, appeared in F_o – F_c maps contoured at 3.5, and had a B factor of <60 Ų. See Table I for summary of refinement statistics and model quality. There are two molecules in the asymmetric unit. The electron density for the bound peptides was very clear in both monomers. The root mean square deviation (rmsd) between the monomers in the asymmetric units of the K^b and the K^bm8 is 0.20 Å over all C atoms, and unless explicitly stated, structural analysis was confined to one K^b-HSV complex and one K^bm8-HSV complex.

CD spectra were measured on a Jasco 810 spectropolarimeter using a thermostatically controlled cuvette at temperatures between 20 and 90°C as described in detail elsewhere (25, 26, 27). Far-UV spectra from 195 to 250 nm were collected and averaged over 10 individual scans; ₂₁₈ measurements for the thermal melting experiments were made at intervals of 0.1°C at a rate of 1°C/min. The midpoint of thermal denaturation (Tm) for each protein was calculated by taking the first derivative of the elipticity data and identifying the inflection point. Both complexes were measured at 30 µg/ml in a solution of 10 mM Tris and 150 mM NaCl (pH 8.0).

	Results

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Greater thermostability of H-2K^b vs H-2K^bm8 complexes

The improved protective immunity against HSV observed in mutant Bm8 mice could reflect a higher affinity for the SSIEFARL determinant by K^bm8 molecules. This might lead to higher determinant density, which might explain the greater diversification of the T cell repertoire in this strain. Therefore, we examined the thermostability of the K^b- and K^bm8-SSIEFARL complexes by CD. Both complexes gave similar spectra at 20°C; however, the Tm of K^b was found to be 7°C higher than K^bm8 bound to the SSIEFARL peptide in two independent experiments (Tm of 61 and 54°C, respectively; Fig. 1), suggesting greater stability and longer half-life of K^b-SSIEFARL complexes in vivo. This finding is consistent with the longer half-life of surface K^b relative to K^bm8 bound to other viral Ags (8). In contrast, the lower stability of K^bm8 complexes indicates that the enhanced protective immunity to HSV in Bm8 mice is not the result of higher levels of Ag presentation and must therefore reflect altered selection of the T cell repertoire.

View larger version (19K): [in this window] [in a new window]   FIGURE 1. Thermostability of polymorphic H-2K molecules bound to SSIEFARL, as revealed by CD spectropolarimetry.

The structures of K^b and K^bm8 complexed to the SSIEFARL have been determined to 2.0- and 1.8-Å resolution, respectively (Table I). Both complexes crystallize in the same space group under identical conditions with isomorphous unit cells. In addition, the freezing protocol for the complexes were identical. Accordingly, conformational differences that are observed between the two crystal structures can be attributed to the polymorphic amino acid differences between K^b and K^bm8. Moreover, all of the regions of interest that are discussed below do not participate in crystal contacts. Table II describes all peptide-H chain (hc) interactions in detail.

View larger version (55K): [in this window] [in a new window]   FIGURE 2. Cut-away view of the Ag-binding clefts of Kb (A) and Kbm8 (B) bound to the SSIEFARL. The 2.0- and 1.8-Å electron density omit maps of SSIEFARL complexed to the respective H-2K molecules are also indicated. Very similar conformations of the peptide were observed, highlighting the exposed Ser1, Glu4, Ala6, and Arg7 residues. Analysis of H-bond and van der Waals contacts contributed to by polymorphic amino acids in Kb (C) and Kbm8 (D) are shown in the same orientation as the views in A and B, respectively. These representations were also superimposed (E) to highlight the mobility of the Arg62 residue and the rigid-body shift in the 1 helix (residues 62–73). The Kb hc is shown in cyan, whereas Kbm8 is shown in green. The peptide ligands are shown in orange and yellow for Kb and Kbm8, respectively.

O

70-N2

22-O

45-O

In K^bm8, the polymorphic residues do not directly contact the peptide. Glu²⁴ is replaced by the smaller Ser residue. The Ser^O group hydrogen bonds with Tyr^45-O, but direct interaction between the polymorphic amino acids at positions 22 and 24 and P2-Ser is lost. The aromatic ring of Phe²² is in the same orientation, and packs against the same residues, as Tyr²² in the K^b structure. A water molecule in the K^bm8 structure fills the cavity that was occupied by the carboxylate of Glu²⁴ and permits a compensatory water-mediated H-bond between P2-Ser and Tyr⁴⁵ (Fig. 2D).

Upon superposition of the K^b- and K^bm8-HSV complexes, the overall rmsd is 0.3 Å for residues 1–180 of the hc. The largest structural differences (>0.5Å in C position) were observed at positions 23, 24, 39, 63–66, 69, and 73 (the C atom of Arg⁶² is displaced 0.4 Å). The conformations of the bound peptides in the two structures were virtually identical. Displacement of the C upon superposition of the peptide backbone revealed only very minor changes restricted to the two N-terminal serine residues of the peptide. The O groups of the side chains of these Ser residues are more divergent: 1 Å apart at position 1; 0.7 Å apart at P2 (see Fig. 2E). Moreover, consistent with the stability measurements, comparison of the average B factor of the peptide in both complexes revealed lower temperature factors for K^b (20.7 Ų} than K^bm8 (28.1 Ų).

The overall impact of the polymorphisms on the structures of K^b- and K^bm8-SSIEFARL complexes include the loss of one direct H-bond to the peptide, and the loss of the H-bonding network that is centered around Glu²⁴ in K^b, and a H-bond to the ₁ helix is also lost in the K^bm8 complex. Structural perturbations can be seen to flow on from position 24. In K^bm8, Tyr⁴⁵ moves toward Ser²⁴, such that the Tyr^45-O groups are 1.0 Å apart in the respective structures (Fig. 2E), and the tilt of the aromatic ring of Tyr⁴⁵ has changed by 45°. In K^b, Tyr⁴⁵ lies flat against the base of ₁ helix, whereas in K^bm8, the plane of the aromatic ring is more perpendicular to the axis of the ₁ helix, nestling within the groove of the helix as well as participating in a unique water-mediated H-bond to P2-Ser of the peptide. The plane of the aromatic ring of Phe⁷⁴, a residue that contacts the polymorphic residue at position 22, has also been adjusted by 30° in the two structures. These polymorphism-mediated structural perturbations result in a local readjustment of the core-packing residues, resulting in a rigid-body shift in the ₁ helix spanning from residues 62 to 73. These changes also influence the positioning and the dynamics of Arg⁶² (Fig. 2, A, B, and E).

In the K^b complex, the Arg⁶² side chain is disordered, with limited electron density observed beyond the C atom of the Arg side chain. Attempts to model the Arg⁶² into a discrete conformation, such as that observed in the K^bm8 complex, resulted in significant negative peaks in the F_o – F_c difference maps, and discontinuous electron density for this side chain in the 2F_o – F_c difference maps as well as high temperature factors. Moreover, simulated-annealing omit maps (28) confirmed the disordered nature of the Arg⁶² side chain for both molecules in the asymmetric unit (data not shown). In contrast, within the K^bm8 complex, the discrete conformation of Arg⁶² side chain (temperature factor of 44 Ų) was clearly evident in the initial electron density maps and later unambiguously confirmed using simulated-annealing omit maps. In the K^bm8 structure, Arg⁶² clearly forms a salt bridge with Glu⁶³, and van der Waals contacts with Trp¹⁶⁷, such that the side chain lies parallel to the ₁ helix (Fig. 2, D and E). The slightly broader cleft in the K^b complex and more optimal packing of the B pocket associated with direct interaction of Glu²⁴ with the peptide act in concert to mobilize Arg⁶².

	Discussion

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We have determined the high-resolution structures of K^b and K^bm8 complexed to the immunodominant HSV determinant gB_498–505. These structures have revealed small rigid-body shifts in the ₁ helix and changes in the H-bonding network associated with the four polymorphic amino acids, altered water structure, and changes in the position and dynamics of Arg⁶². The four polymorphic amino acids present between K^b and K^bm8 are not in a position to interact with the TCR directly, consistent with previous structures of related complexes (8). In our structures, the bound conformation of SSIEFARL in the K^b and K^bm8 complexes is very similar, with subtle structural perturbations evident toward the N terminus of the peptide. Subtle changes in the helices bounding the peptide can impact upon T cell recognition and thymic selection, as highlighted, for example, by our recent studies on the ligand repertoire and conformation of HLA B44 allotypes (2). Moreover, differences in T cell selection by K^b and K^bm8 have previously been documented (15) and suggested that altered peptide repertoire and conformation of MHC-peptide complexes can impact significantly on T cell selection in B6 and Bm8 mice. Consistent with this concept was the ability of certain mAb to differentiate between cells expressing K^b and K^bm8 (17).

The substitution of Glu²⁴ to Ser²⁴ in K^bm8 not only substantially reduces the electronegative potential of the B pocket of these molecules but also results in the loss of a direct H-bond between the K^bm8 hc and the peptide ligand. A series of conformational adjustments are observed to compensate for the loss of this interaction with changes in the hydrophobic packing of the B pocket and surrounding residues evident. Interestingly, the loss of these interactions probably accounts for the considerable decrease in the thermostability of the complex as measured by CD and increased crystallographic temperature factors for the peptide. Earlier epitope stabilization studies (29) have demonstrated that K^bm8 molecules expressed on TAP-deficient cells bind to SSIEFARL in a manner comparable to the wild-type K^b molecules. Taken together with the lower thermostability of K^bm8 complexes, we predict that the stability of these surface-loaded molecules will be much reduced in K^bm8, as observed for VSV8 and SEV9 peptides (8). In addition to the conformational changes directly associated with the four polymorphic amino acids, we also see changes in the orientation and mobility of Arg⁶², a shared residue on the hc ₁ helix. Comparison of the structures of previously reported shared viral ligands of K^b and K^bm8 also reveal variability in the orientation of Arg⁶² (8). A role for the positioning and dynamics of Arg⁶² in locking in the N termini of bound peptides in HLA B27 complexes has also recently been noted (9). Moreover, a ligand-dependent switch in the orientation of Arg⁶² has been observed in structures of HLA B8 complexed to EBV (FLRGRAYGL) and HIV (GGKKKYKL) epitopes (30, 31). The Phe group of the EBV determinant sterically restricts positioning of Arg⁶², forcing it to project into the solvent, whereas the Arg⁶² packs down in B8/GGKKKYKL structure in a manner analogous to our K^bm8 structure. Fig. 3A highlights this remarkable variability in the positioning of Arg⁶² in selected unligated MHC-peptide complexes.

View larger version (22K): [in this window] [in a new window]   FIGURE 3. A, Positioning of Arg62 in unligated class I complexes. Superposition of selected structures of other class I molecules that possess an Arg62 highlight the variability in the positioning of this residue in unligated complexes. Color and PDB codes are as follows: Kbm8-SSIEFARL (blue), HLA B*0801-FLRGRAYGL (cyan, 1MO5) (30 ), HLA B*0801-GGRKKYKL (green, 1AGB) (31 ), H-2Kb-PKB1 (red, 1KJ3) (22 ), HLA B*2705-M9 (orange, 1JGE) (10 ), HLA B*2709-S10R (yellow, 1JGD) (9 ), and Kbm1-VSV8 (purple, 1FZJ) (8 ). B and C, Plasticity in the positioning and conserved interaction of Arg62 with CDR1 residues in existing MHC-peptide-TCR complexes. Top (B) and side (C) views of the hc of HLA B8 in complex with LC13 TCR (1MI5 red) (33 ), Kb in complex with Kb5-C20 TCR (1KJ2 orange) (22 ), Kb-DEV8 in complex with 2C TCR (2CKB green) (37 ), and Kb-VSV8 in complex with BM3.3 TCR (1NAM) were superimposed, and the position of the Arg and its conserved contacts to the CDR1 residues are indicated. Only Arg62 from Kb in complex with the Kb5-C20 TCR makes a salt bridge interaction.

During infection with HSV, B6 CD8⁺ T cells only recognize SSIEFARL bound to cognate K^b molecules and not to the K^bm8 allelic variant. Conversely, a subset of Bm8 CD8⁺ T cells cross-react on K^b targets presenting the SSIEFARL determinant (6). The ability of T cells to discriminate between complexes suggests the conformational differences observed have functional relevance. Analysis of TCR usage in HSV infection has revealed that Bm8 mice use more diverse V/V combinations, whereas B6 mice use dominant V2, V10, and V8 gene families (Table III). Differences in the structures of the complexes studied here are focused around the N terminus of the ligand and surrounding regions of the ₁ helix and can only, assuming a conserved diagonal TCR docking framework, directly affect the V chain. Any bias in the -chain most likely reflects the particular V/V pairing. The exaggerated use of V2 in up to 70% of all B6 SSIEFARL-specific T cells may therefore result from differences in this structurally disparate end of the complexes. A distinctive feature of V2-positive TCRs isolated from infected B6 mice is the presence of an acidic residue in the CDR1 loop (Table III). Conversely, the CDR1 regions used in many of the K^bm8-restricted CD8⁺ T cells such as V5 and V6-1 (6) do not contain an electronegative amino acid in their CDR1 loops. Given the conserved nature of CDR1-Arg⁶² interaction, this potential salt bridge is available for both K^b and K^bm8 complexes, and yet only K^b-restricted CD8⁺ T cells demonstrate V2 bias. Moreover, in V2-, V1-, and V5-positive TCRs, the acidic residue is at position 26, a position previously shown to salt bridge to Arg⁶² in the Kb5-C20 TCR-H-2K^b complex structure (22) and positioned in a region of CDR1 that dominantly interacts with Arg⁶² in all other ternary complex structures where an Arg⁶² is present (32, 33). Therefore, we speculate that the V2 bias in CD8⁺ T cells from B6 mice results from selection of TCRs that can efficiently ligate the highly mobile Arg⁶² on the ₁ helix of K^b via salt bridge formation. TCR binding to K^b/SSIEFARL will have a greater entropic penalty than binding to the equivalent K^bm8 complex because of the mobility of Arg⁶² in the K^b complexes. Given that TCR-MHC interactions are generally enthalpically driven, which reflects the requirement for surface complementation, and that TCR ligation involves entropic penalties associated with the greater order of residues and solvent molecules at the MHC-TCR interface (34, 35), the biased selection of V2 in B6 mice may reflect the repertoire constraints in overcoming a greater entropic penalty for recognition of this complex. This would be consistent with the narrower expansion of SSIEFARL-specific CD8 T cells in B6 mice. In contrast, the ordered Arg⁶² conformation in K^bm8 complexes imparts much less constraint on the T cell repertoire usage of Bm8 mice, and this leads to more diverse and higher functional avidity of the CD8⁺ T cell response. This hypothesis is currently under investigation by studying the thermodynamics of soluble forms of SSIEFARL-specific TCRs binding to their cognate MHC-peptide molecules using both BIAcore and calorimetric methodologies in a manner analogous to Davis and colleagues (36).

View this table: [in this window] [in a new window]   Table III. CDR1 sequences of commonly used V chains used in the HSV-1 CD8+ T cell response in B6 and Bm8 micea

	Acknowledgments

 
We thank A. Brooks and A. Winterhalter for the original K^b expression construct. We thank the staff at BioCARS and the Australian Synchrotron Research Program for assistance.

	Footnotes

 
¹ J.R. is supported by a Wellcome Trust Senior Research Fellowship in Biomedical Science in Australia. A.W.P. is a C. R. Roper Fellow of the Faculty of Medicine, Dentistry, and Health Science at the University of Melbourne. This work was supported by the National Health and Medical Research Council, the Roche Organ Transplantation Research Foundation, the Australian Research Council, and the Juvenile Diabetes Research Foundation.

² Coordinates of each complex have been deposited in the Brookhaven Protein Data Bank as 1T0M (K^b/HSV) and 1T0N(k^bm8/HSV).

³ A.I.W. and N.A.B. contributed equally to this work.

⁴ A.W.P and J.R. are joint senior authors.

⁵ Address correspondence and reprint requests to Dr. Anthony W. Purcell, Department of Microbiology and Immunology, University of Melbourne, Victoria 3010, Australia; or Dr. Jamie Rossjohn, Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia. E-mail addresses: apurcell{at}unimelb.edu.au and jamie.rossjohn{at}med.monash.edu.au

⁶ Abbreviations used in this paper: VSV, vesicular stomatitis virus; SEV, Sendai virus; rmsd, root mean square deviation; CD, circular dichroism; Tm, midpoint of thermal denaturation; hc, H chain.

Received for publication February 4, 2004. Accepted for publication April 20, 2004.

	References

Top Abstract Introduction Materials and Methods Results Discussion References

 

1. Little, A. M., P. Parham. 1999. Polymorphism and evolution of HLA class I and II genes and molecules. Rev. Immunogenet. 1:105.[Medline]
2. Macdonald, W. A., A. W. Purcell, N. Mifsud, L. K. Ely, D. S. Williams, L. Chang, J. J. Gorman, C. S. Clements, L. Kjer-Nielsen, D. M. Koelle, et al 2003. A naturally selected dimorphism within the HLA-B44 supertype alters class I structure, peptide repertoire and T cell recognition. J. Exp. Med. 198:679.[Abstract/Free Full Text]
3. Hildebrand, W. H., H. R. Turnquist, K. R. Prilliman, H. D. Hickman, E. L. Schenk, M. M. McIlhaney, J. C. Solheim. 2002. HLA class I polymorphism has a dual impact on ligand binding and chaperone interaction. Hum. Immunol. 63:248.[Medline]
4. Neisig, A., R. Wubbolts, X. Zang, C. Melief, J. Neefjes. 1996. Allele-specific differences in the interaction of MHC class I molecules with transporters associated with antigen processing. J. Immunol. 156:3196.[Abstract]
5. Wallace, M. E., R. Keating, W. R. Heath, F. R. Carbone. 1999. The cytotoxic T-cell response to herpes simplex virus type 1 infection of C57BL/6 mice is almost entirely directed against a single immunodominant determinant. J. Virol. 73:7619.[Abstract/Free Full Text]
6. Messaoudi, I., J. LeMaoult, B. M. Metzner, M. J. Miley, D. H. Fremont, J. Nikolich-Zugich. 2001. Functional evidence that conserved TCR CDR₃ loop docking governs the cross-recognition of closely related peptide:class I complexes. J. Immunol. 167:836.[Abstract/Free Full Text]
7. Nathenson, S. G., J. Geliebter, G. M. Pfaffenbach, R. A. Zeff. 1986. Murine major histocompatibility complex class-I mutants: molecular analysis and structure-function implications. Annu. Rev. Immunol. 4:471.[Medline]
8. Rudolph, M. G., J. A. Speir, A. Brunmark, N. Mattsson, M. R. Jackson, P. A. Peterson, L. Teyton, I. A. Wilson. 2001. The crystal structures of K^bm1 and K^bm8 reveal that subtle changes in the peptide environment impact thermostability and alloreactivity. Immunity 14:231.[Medline]
9. Hillig, R. C., M. Huelsmeyer, W. Saenger, K. Welfle, R. Misselwitz, H. Welfle, C. Kozerski, A. Volz, B. Uchanska-Ziegler, A. Ziegler. 2004. Thermodynamic and structural analysis of peptide- and allele-dependent properties of two HLA-B27 subtypes exhibiting differential disease association. J. Biol. Chem. 279:652.[Abstract/Free Full Text]
10. Hulsmeyer, M., R. C. Hillig, A. Volz, M. Ruhl, W. Schroder, W. Saenger, A. Ziegler, B. Uchanska-Ziegler. 2002. HLA-B27 subtypes differentially associated with disease exhibit subtle structural alterations. J. Biol. Chem. 277:47844.[Abstract/Free Full Text]
11. Fiorillo, M. T., G. Greco, M. Maragno, I. Potolicchio, A. Monizio, M. L. Dupuis, R. Sorrentino. 1998. The naturally occurring polymorphism Asp¹¹⁶His¹¹⁶, differentiating the ankylosing spondylitis-associated HLA-B*2705 from the non-associated HLA-B*2709 subtype, influences peptide-specific CD8 T cell recognition. Eur. J. Immunol. 28:2508.[Medline]
12. Fiorillo, M. T., L. Meadows, M. D’Amato, J. Shabanowitz, D. F. Hunt, E. Appella, R. Sorrentino. 1997. Susceptibility to ankylosing spondylitis correlates with the C-terminal residue of peptides presented by various HLA-B27 subtypes. Eur. J. Immunol. 27:368.[Medline]
13. Garcia-Peydro, M., M. Marti, J. Lopez de Castro. 1999. High T cell epitope sharing between two HLA-B27 subtypes (B*2705 and B*2709) differentially associated to ankylosing spondylitis. J. Immunol. 163:2299.[Abstract/Free Full Text]
14. Nikolic-Zugic, J., F. R. Carbone. 1990. The effect of mutations in the MHC class I peptide binding groove on the cytotoxic T lymphocyte recognition of the K^b-restricted ovalbumin determinant. Eur. J. Immunol. 20:2431.[Medline]
15. Stefanski, H. E., S. C. Jameson, K. A. Hogquist. 2000. Positive selection is limited by available peptide-dependent MHC conformations. J. Immunol. 164:3519.[Abstract/Free Full Text]
16. de Waal, L. P., W. M. Kast, R. W. Melvold, C. J. Melief. 1983. Regulation of the cytotoxic T lymphocyte response against Sendai virus analyzed with H-2 mutants. J. Immunol. 130:1090.[Medline]
17. Clark, S. S., J. Forman. 1983. Structure function relationship of class I MHC molecules. Surv. Immunol. Res. 2:203.[Medline]
18. Messaoudi, I., J. A. Guevara Patino, R. Dyall, J. LeMaoult, J. Nikolich-Zugich. 2002. Direct link between mhc polymorphism, T cell avidity, and diversity in immune defense. Science 298:1797.[Abstract/Free Full Text]
19. Macdonald, W., D. S. Williams, C. S. Clements, J. J. Gorman, L. Kjer-Nielsen, A. G. Brooks, J. McCluskey, J. Rossjohn, A. W. Purcell. 2002. Identification of a dominant self-ligand bound to three HLA B44 alleles and the preliminary crystallographic analysis of recombinant forms of each complex. FEBS Lett. 527:27.[Medline]
20. Kundrot, C. E.. 2004. Which strategy for a protein crystallization project?. Cell. Mol. Life Sci. 61:525.[Medline]
21. Weber, P. C.. 1997. Overview of protein crystallization methods. Methods Enzymol. 276:(Pt. A):13.
22. Reiser, J. B., C. Gregoire, C. Darnault, T. Mosser, A. Guimezanes, A. M. Schmitt-Verhulst, J. C. Fontecilla-Camps, G. Mazza, B. Malissen, D. Housset. 2002. A T cell receptor CDR3 loop undergoes conformational changes of unprecedented magnitude upon binding to a peptide/MHC class I complex. Immunity 16:345.[Medline]
23. Brunger, A. T., P. D. Adams, G. M. Clore, W. L. DeLano, P. Gros, R. W. Grosse-Kunstleve, J. S. Jiang, J. Kuszewski, M. Nilges, N. S. Pannu, et al 1998. Crystallography & NMR system: a new software suite for macromolecular structure determination. Acta Crystallogr. D 54:(Pt. 5):905.[Medline]
24. Jones, T. A., J. Y. Zou, S. W. Cowan, S. W. Kjeldgaard. 1991. Improved methods for building protein models in electron density maps and the location of errors in these models. Acta Crystallogr. A 47:(Pt. 2):110.
25. Webb, A. I., M. A. Dunstone, W. Chen, M.-I. Aguilar, Q. Chen, H. Jackson, L. Chang, L. Kjer-Nielsen, T. Beddoe, J. McCluskey, et al 2004. Functional and structural characteristics of NY-ESO-1 related HLA-A2 restricted epitopes and the design of a novel immunogenic analogue. J. Biol. Chem. 279:23438.[Abstract/Free Full Text]
26. Rognan, D., L. Scapozza, G. Folkers, A. Daser. 1995. Rational design of nonnatural peptides as high-affinity ligands for the HLA-B*2705 human leukocyte antigen. Proc. Natl. Acad. Sci. USA 92:753.[Abstract/Free Full Text]
27. Shields, M. J., W. Hodgson, R. K. Ribaudo. 1999. Differential association of ₂-microglobulin mutants with MHC class I heavy chains and structural analysis demonstrate allele-specific interactions. Mol. Immunol. 36:561.[Medline]
28. Brunger, A. T., P. D. Adams, L. M. Rice. 1997. New applications of simulated annealing in X-ray crystallography and solution NMR. Structure 5:325.[Medline]
29. Huard, R., R. Dyall, J. Nikolic-Zugic. 1997. The critical role of a solvent-exposed residue of an MHC class I-restricted peptide in MHC-peptide binding. Int. Immunol. 9:1701.[Abstract/Free Full Text]
30. Kjer-Nielsen, L., C. S. Clements, A. G. Brooks, A. W. Purcell, M. R. Fontes, J. McCluskey, J. Rossjohn. 2002. The structure of HLA-B8 complexed to an immunodominant viral determinant: peptide-induced conformational changes and a mode of MHC class I dimerization. J. Immunol. 169:5153.[Abstract/Free Full Text]
31. Reid, S. W., S. McAdam, K. J. Smith, P. Klenerman, C. A. O’Callaghan, K. Harlos, B. K. Jakobsen, A. J. McMichael, J. I. Bell, D. I. Stuart, E. Y. Jones. 1996. Antagonist HIV-1 Gag peptides induce structural changes in HLA B8. J. Exp. Med. 184:2279.[Abstract/Free Full Text]
32. Reiser, J. B., C. Darnault, C. Gregoire, T. Mosser, G. Mazza, A. Kearney, P. A. van der Merwe, J. C. Fontecilla-Camps, D. Housset, B. Malissen. 2003. CDR3 loop flexibility contributes to the degeneracy of TCR recognition. Nat. Immunol. 4:241.[Medline]
33. Kjer-Nielsen, L., C. S. Clements, A. W. Purcell, A. G. Brooks, J. C. Whisstock, S. R. Burrows, J. McCluskey, J. Rossjohn. 2003. A structural basis for the selection of dominant T cell receptors in antiviral immunity. Immunity 18:53.[Medline]
34. Boniface, J. J., Z. Reich, D. S. Lyons, M. M. Davis. 1999. Thermodynamics of T cell receptor binding to peptide-MHC: evidence for a general mechanism of molecular scanning. Proc. Natl. Acad. Sci. USA 96:11446.[Abstract/Free Full Text]
35. Willcox, B. E., G. F. Gao, J. R. Wyer, J. E. Ladbury, J. I. Bell, B. K. Jakobsen, P. A. van der Merwe. 1999. TCR binding to peptide-MHC stabilizes a flexible recognition interface. Immunity 10:357.[Medline]
36. Krogsgaard, M., N. Prado, E. J. Adams, X. L. He, D. C. Chow, D. B. Wilson, K. C. Garcia, M. M. Davis. 2003. Evidence that structural rearrangements and/or flexibility during TCR binding can contribute to T cell activation. Mol. Cell. 12:1367.[Medline]
37. Garcia, K. C., M. Degano, R. L. Stanfield, A. Brunmark, M. R. Jackson, P. A. Peterson, L. Teyton, I. A. Wilson. 1996. An T cell receptor structure at 2.5 Å and its orientation in the TCR-MHC complex. Science 274:209.[Abstract/Free Full Text]
38. Zernich, D., A. W. Purcell, W. A. Macdonald, L. Kjer-Nielsen, L. K. Ely, N. Laham, T. L. Crockford, N. A. Mifsud, M. Bharadwaj, L. Chang, et al. 2004. Natural HLA class I polymorphism controls the pathway of antigen presentation and susceptibility to viral evasion. J. Exp. Med. In press.
39. Lefranc, M.-P.. 2003. IMGT, the international ImMunoGeneTics database. Nucleic Acids Res. 31:307.[Abstract/Free Full Text]

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