Steiner L A, Pardo A G, Margolies M N
Biochemistry. 1979 Sep 18;18(19):4068-80. doi: 10.1021/bi00586a003.
The amino acid sequence of the heavy-chain variable region of the crystallizable human myeloma protein Dob has been determined. This protein has previously been shown to have a deletion in the hinge region [Lopes, A. D., & Steiner, L. A. (1973) Fed. Proc., Fed. Am. Soc. Exp. Biol. 32, 1003; Steiner, L. A., & Lopes, A. D. (1979) Biochemistry (preceding paper in this issue)]. The complete sequence was established by analysis, in the automated sequenator, of the intact Fd' piece and of three large overlapping fragments prepared from Fd' by digestion with cyanogen bromide, by tryptic digestion of the citraconylated Fd', and by cleavage with hydroxylamine. Portions of the sequence were confirmed by examination of the amino acid composition and the partial sequence of a variety of small peptides obtained by enzymatic degradation. The Dob heavy-chain variable region appears to belong to the VHIII subgroup, but there are several unusual substitutions. Residue 45 in the Dob sequence is proline, although all other known heavy-chain sequences in man, mouse, rabbit, and guinea pig have leucine at this position. Positions 10 (aspartic acid), 68 (alanine), and 82 (leucine) in the Dob sequence are also atypical. There is no deleted segment in the variable region of the Dob heavy chain nor any abnormality in the variable-constant joining region. The hinge-region deletion appears to be the only gross structural anomaly in the Dob heavy chain.
已确定可结晶的人骨髓瘤蛋白Dob重链可变区的氨基酸序列。此前已证明该蛋白在铰链区存在缺失[洛佩斯，A. D.，& 施泰纳，L. A.（1973年）《联邦程序》，美国实验生物学联合会会刊32，1003；施泰纳，L. A.，& 洛佩斯，A. D.（1979年）《生物化学》（本期前一篇论文）]。通过在自动测序仪中分析完整的Fd'片段以及用溴化氰消化Fd'制备的三个大的重叠片段、对柠檬酰化Fd'进行胰蛋白酶消化以及用羟胺裂解来确定完整序列。通过检查氨基酸组成以及对通过酶促降解获得的各种小肽的部分序列来确认部分序列。Dob重链可变区似乎属于VHIII亚组，但存在几个不寻常的取代。Dob序列中的第45位残基是脯氨酸，而人、小鼠、兔和豚鼠中所有其他已知的重链序列在该位置都是亮氨酸。Dob序列中的第10位（天冬氨酸）、第68位（丙氨酸）和第82位（亮氨酸）也不典型。Dob重链的可变区没有缺失片段，可变 - 恒定连接区也没有任何异常。铰链区缺失似乎是Dob重链中唯一明显的结构异常。
