PT  - JOURNAL ARTICLE
AU  - Rojo, S
AU  - Aparicio, P
AU  - Hansen, J A
AU  - Choo, S Y
AU  - López de Castro, J A
TI  - Structural analysis of an HLA-B27 functional variant, B27d, detected in American blacks.
DP  - 1987 Nov 15
TA  - The Journal of Immunology
PG  - 3396--3401
VI  - 139
IP  - 10
4099  - http://www.jimmunol.org/content/139/10/3396.short
4100  - http://www.jimmunol.org/content/139/10/3396.full
SO  - J. Immunol.1987 Nov 15; 139
AB  - The structure of a new functional variant B27d has been established by comparative peptide mapping and radiochemical sequencing. This analysis completes the structural characterization of the six known histocompatibility leukocyte antigen (HLA)-B27 subtypes. The only detected amino acid change between the main HLA-B27.1 subtype and B27d is that of Tyr59 to His59. Position 59 has not been previously found to vary among class I HLA or H-2 antigens. Such substitution accounts for the reported isoelectric focusing pattern of this variant. HLA-B27d is the only B27 variant found to differ from other subtypes by a single amino acid replacement. The nature of the change is compatible with its origin by a point mutation from HLA-B27.1. Because B27d was found only in American blacks and in no other ethnic groups, it is suggested that this variant originated as a result of a mutation of the B27.1 gene that occurred within the black population.