Pawlita M, Potter M, Rudikoff S
J Immunol. 1982 Aug;129(2):615-8.
Complete kappa-chain variable region sequences were determined for 10 light chains from anti-beta-(1,6)-D-galactan-binding monoclonal antibodies. Eight of these light chains were from IgM and two from IgG proteins. Seven of the eight IgM light chains were identical from position 1 to 95, the region encoded by the light chain variable region gene. The eighth differed at a single framework position. The two IgG light chains were identical in sequence and differed from the IgM light chains at two framework positions. All 10 light chains have an lle at position 96, as has been previously reported in 5 of 6 anti-galactan myeloma proteins. This residue is the first amino acid normally encoded by the light chain J gene. None of the germ line J genes encodes an lle at position 96, and furthermore the lle codon cannot be generated by alterations in the frame of recombination between the codon for amino acid 95 and J gene codons. These light chains are thus the product of an unusual and reproducible recombination event that appears to employ an extra codon at the 3' end of the variable region gene. Three different J segments are potentially used in these light chains J1 or J2 was found in three chains and J5 in seven.
测定了来自抗β-(1,6)-D-半乳聚糖结合单克隆抗体的10条轻链的完整κ链可变区序列。其中8条轻链来自IgM蛋白，2条来自IgG蛋白。8条IgM轻链中的7条在第1至95位相同，该区域由轻链可变区基因编码。第8条在一个框架位置上有所不同。两条IgG轻链序列相同，在两个框架位置上与IgM轻链不同。所有10条轻链在第96位都有一个异亮氨酸，这与之前报道的6种抗半乳聚糖骨髓瘤蛋白中的5种情况相同。该残基是通常由轻链J基因编码的第一个氨基酸。种系J基因中没有一个在第96位编码异亮氨酸，此外，异亮氨酸密码子不能通过95位氨基酸密码子与J基因密码子之间重组框架的改变而产生。因此，这些轻链是一种不寻常且可重复的重组事件的产物，该事件似乎在可变区基因的3'端使用了一个额外的密码子。这些轻链中潜在地使用了三种不同的J片段，三条链中发现了J1或J2，七条链中发现了J5。
