CDR-H3 diversity is not required for antigen recognition by synthetic antibodies.
CDR-H3 diversity is not required for antigen recognition by synthetic antibodies.
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DOI：
10.1016/j.jmb.2012.11.037
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发表时间：
2013-02-22
影响因子：
5.6
通讯作者：
Sidhu, Sachdev S.
中科院分区：
文献类型：
--
作者：
Persson, Helena;Ye, Wei;Wernimont, Amy;Adams, Jarrett J.;Koide, Akiko;Koide, Shohei;Lam, Robert;Sidhu, Sachdev S.
构建了在重链（CDR-H3）和轻链（CDR-L3）的第三互补决定区中具有等同化学多样性的合成噬菌体展示抗体库，这与天然抗体形成对比，其中由于产生抗体编码基因的遗传机制，CDR-H3比CDR-L3多样得多。令人惊讶的是，合成库产生了许多含有突变的CDR-L3序列但含有固定的CDR-H3序列的功能性抗体。对识别10种不同抗原但含有共同CDR-H3环的抗体的丙氨酸扫描分析显示，在大多数情况下，固定的CDR-H3序列能够有利地促进抗原识别，但在某些情况下，该环在功能上是惰性的。对与抗原复合的一种这样的抗体的结构分析显示，惰性CDR-H3环仍然高度掩埋在抗体-抗原界面处。总而言之，这些结果表明，产生以高亲和力和特异性识别不同蛋白抗原的抗体并不一定需要CDR-H3多样性，如果有机会，CDR-L3很容易在抗原识别中发挥主导作用。这些结果与从天然抗体的分析得到的抗原识别的普遍接受的观点形成对比，在该观点中，CDR-H3被假定为占主导地位，而CDR-L3被假定为起辅助作用。此外，结果表明，天然抗体功能受到遗传限制，并且应该可以通过扩展CDR-L3的多样性来开发更多功能的合成抗体文库，超出自然界中观察到的。
A synthetic phage-displayed antibody repertoire was constructed with equivalent chemical diversity in the third complementarity-determining regions of the heavy (CDR-H3) and light chains (CDR-L3), which contrasts with natural antibodies in which CDR-H3 is much more diverse than CDR-L3 due to the genetic mechanisms that generate antibody encoding genes. Surprisingly, the synthetic repertoire yielded numerous functional antibodies that contained mutated CDR-L3 sequences but a fixed CDR-H3 sequence. Alanine-scanning analysis of antibodies that recognized ten different antigens but contained a common CDR-H3 loop showed that, in most cases, the fixed CDR-H3 sequence was able to contribute favorably to antigen recognition, but in some cases, the loop was functionally inert. Structural analysis of one such antibody in complex with antigen showed that the inert CDR-H3 loop was nonetheless highly buried at the antibody-antigen interface. Taken together, these results show that CDR-H3 diversity is not necessarily required for the generation of antibodies that recognize diverse protein antigens with high affinity and specificity, and if given the chance, CDR-L3 readily assumes the dominant role for antigen recognition. These results contrast with the commonly accepted view of antigen recognition derived from the analysis of natural antibodies, in which CDR-H3 is presumed to be dominant and CDR-L3 is presumed to play an auxiliary role. Furthermore, the results show that natural antibody function is genetically constrained, and it should be possible to develop more functional synthetic antibody libraries by expanding the diversity of CDR-L3 beyond what is observed in nature.
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影响因子：
--
作者：
Birtalan, Sara;Fisher, Robert D.;Sidhu, Sachdev S.
通讯作者：
Sidhu, Sachdev S.
影响因子：
5.6
作者：
Birtalan, Sara;Zhang, Yingnan;Sidhu, Sachdev S.
通讯作者：
Sidhu, Sachdev S.
影响因子：
56.9
作者：
Bostrom, Jenny;Yu, Shang-Fan;Fuh, Germaine
通讯作者：
Fuh, Germaine
DOI：
10.1107/s0907444909042073
发表时间：
2010-01
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Chen VB;Arendall WB 3rd;Headd JJ;Keedy DA;Immormino RM;Kapral GJ;Murray LW;Richardson JS;Richardson DC
通讯作者：
Richardson DC
影响因子：
5.6
作者：
MacCallum, RM;Martin, ACR;Thornton, JM
通讯作者：
Thornton, JM