CRYSTAL-STRUCTURE OF A DIABODY, A BIVALENT ANTIBODY FRAGMENT
CRYSTAL-STRUCTURE OF A DIABODY, A BIVALENT ANTIBODY FRAGMENT
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DOI：
10.1016/s0969-2126(94)00123-5
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发表时间：
1994-12-15
期刊：
影响因子：
5.7
通讯作者：
WILLIAMS, RL
中科院分区：
文献类型：
--
作者：
PERISIC, O;WEBB, PA;WILLIAMS, RL
背景：双链抗体是一种二聚体抗体片段。在每个多肽中，一个重链可变区(V-H)连接到一个轻链可变区(V-L)，但与单链FV片段不同，每个抗原结合部位是由两个不同多肽中的一个V-H和一个V-L结构域配对形成的。因此DIABADIES有两个抗原结合部位，并且可以是双特异性的。结果：通过氨基末端V-H和羧基末端V-L之间柔性的五个残基的多肽连接物，确定了二价体的2.6埃分辨结构。晶体的不对称单元由四个多肽组成，其中一个多肽的连接子位于V-H和V-L结构域之间。在每个鞭毛虫内，两个关联的V-H和V-L结构域通过V-H结构域进行背靠背相互作用，并且在不对称单元中两个鞭毛虫之间存在广泛的V-L-V-L界面。结论：该鞭毛虫的结构与分子模拟预测的结构非常相似。针对细胞表面抗原的Diabody应该能够将两个细胞聚集在一起，例如在细胞靶向治疗中，因为Diabody的两个抗原结合部位位于分子的相反两端，相隔类似于65埃。
Background: Diabodies are dimeric antibody fragments. In each polypeptide, a heavy-chain variable domain (V-H) is linked to a light-chain variable domain (V-L) but unlike single-chain Fv fragments, each antigen-binding site is formed by pairing of one V-H and one V-L domain from the two different polypeptides. Diabodies thus have two antigen-binding sites, and can be bispecific. Direct structural evidence is lacking for the connections and dimeric interactions between the two polypeptides of the diabody.Results: The 2.6 Angstrom resolution structure has been determined for a bivalent diabody with a flexible five-residue polypeptide linker between the (amino-terminal) V-H and (carboxy-terminal) V-L domains. The asymmetric unit of the crystal consists of four polypeptides comprising two diabodies; for one of these polypeptides the linker can be traced between the V-H and V-L domains. Within each diabody the two associated V-H and V-L domains make back-to-back interactions through the V-H domains, and there is an extensive V-L-V-L interface between the two diabodies in the asymmetric unit.Conclusions: The structure of the diabody is very similar to that which had been predicted by molecular modelling. Diabodies directed against cell-surface antigens should be capable of bringing together two cells, such as in cell-targeted therapy, because the two antigen-binding sites of the diabody are at opposite ends of the molecule and separated by similar to 65 Angstrom.