Molecular Recognition and Signal Transduction in Antibodie

本文报道了由V_H和V_L结构域组成的抗原识别单元Fv片段的同位素编辑核磁共振研究。Fv片段是通过clostripain酶切短链抗丹酚小鼠IgG2a单克隆抗体获得的。制备了多种稳定同位素标记的抗丹酚Fv类似物。基于稳定同位素辅助异核和同核二维核磁共振谱，得出结论：1)dansylring通过tyr1 - 96h和tyr1 - 104h结合到重链第三高变区H3环的两端；2)在没有DNS-Lys的情况下，H3环表现出明显的内运动；3)DNS-Lys的结合导致H3环的动力学结构发生显著变化。

An isotope-edited nuclear magnetic resonance study is reported of the Fv fragment, which is the smallest antigen recognition unit composed of V_H and V_L domains. The Fv fragment has been obtained by clostripain digestion of a short-chain anti-dansyl mouse IgG2a monoclonal antibody. A variety of stable-isotope labeled anti-dansyl Fv analogues have been prepared. On the basis of stable isotope-aided heteronuclear and homonuclear two-dimensional NMR spectra, it has been concluded that 1) the dansylring is bound through Tyr-96H and Tyr-104H to both ends of H3 loop, the third hypervariable region of the heavy chain, 2) in the absence of DNS-Lys, the H3 loop displays a significant degree of internal motion and 3) binding of DNS-Lys induces a significant change in the dynamical structure of the H3 loop.