Trägärdh L, Rask L, Wiman K, Fohlman J, Peterson P A
Proc Natl Acad Sci U S A. 1979 Nov;76(11):5839-42. doi: 10.1073/pnas.76.11.5839.
The classical human transplantation antigens, derived from the HLA-A, -B, and -C loci, are cell-surface-expressed glycoproteins. On the exterior of the cell the transplantation antigen heavy chain exposes two disulfide-containing domains and a glycosylated NH2-terminal extension. The disulfide-containing domain closest to the membrane has been isolated and its amino acid sequence has been determined. The HLA antigens used for the sequence analysis were derived from two and possibly three loci and comprised several allelic forms. The primary structure was remarkably invariant, and amino acid variations were observed only at three positions. Whether this suggests that the allelic variation of the HLA antigens is preferentially confined to other regions of the molecule or is a result of fortuitous selection of peptides remains to be established. The sequenced portion of the HLA antigen heavy chain is as homologous to beta 2-microglobulin and immunoglobulin light and heavy chains as are the latter to one another. This observation strengthens the notion that the transplantation antigens and the immunoglobulins are evolutionarily related.
源自HLA - A、- B和 - C基因座的经典人类移植抗原是细胞表面表达的糖蛋白。在细胞外部，移植抗原重链暴露两个含二硫键的结构域和一个糖基化的NH2末端延伸。最靠近膜的含二硫键结构域已被分离出来，其氨基酸序列也已确定。用于序列分析的HLA抗原源自两个可能三个基因座，包含几种等位基因形式。一级结构非常稳定，仅在三个位置观察到氨基酸变异。这是否表明HLA抗原的等位基因变异优先局限于分子的其他区域，或者是肽段偶然选择的结果，仍有待确定。HLA抗原重链的测序部分与β2 - 微球蛋白以及免疫球蛋白轻链和重链的同源性，与后两者之间的同源性相同。这一观察结果强化了移植抗原与免疫球蛋白在进化上相关的观点。
