Kehoe J M, Capra J D
Proc Natl Acad Sci U S A. 1971 Sep;68(9):2019-21. doi: 10.1073/pnas.68.9.2019.
Cyanogen bromide fragments were isolated from the heavy chains of three human IgG myeloma proteins of the V(H)III subgroup, sequenced by an automated method, and localized to the variable region. Inspection of these sequences, together with corresponding stretches from both human and animal proteins (studied in other laboratories) led to the detection of two additional hypervariable regions characteristic of the V(H) segment of immunoglobulin heavy chains. These areas of hypervariability, involving heavy-chain residues 86-91 and 101-109, were separated by a region of relative constancy. The close relationship of these two hypervariable regions, and the previously described first heavy-chain hypervariable region (residues 31-37), to the first heavy-chain disulphide bridge implies that the three hypervariable areas might be in close steric approximation in native immunoglobulin molecules. Examination of the sequences of the terminal portion of V(H) of all these proteins (the segment from residue 95 to the beginning of homology region C(H)l) revealed that no subgroup-specific residues could be identified in this area. Thus, heavy-chain subgroup distinctions may not extend through the entire variable region.
从V(H)III亚组的三种人IgG骨髓瘤蛋白的重链中分离出溴化氰片段，采用自动化方法进行测序，并定位到可变区。对这些序列以及来自人和动物蛋白（在其他实验室研究）的相应片段进行检查，发现了免疫球蛋白重链V(H)片段特有的另外两个高变区。这些高变区涉及重链残基86 - 91和101 - 109，它们被一个相对恒定的区域隔开。这两个高变区以及先前描述的第一个重链高变区（残基31 - 37）与第一个重链二硫键的密切关系表明，在天然免疫球蛋白分子中，这三个高变区可能在空间上紧密相邻。对所有这些蛋白V(H)末端部分的序列（从残基95到同源区C(H)1开始的片段）进行检查发现，在该区域无法鉴定出亚组特异性残基。因此，重链亚组的区分可能不会贯穿整个可变区。
