Faiman G A, Levy R, Anglister J, Horovitz A
Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
J Biol Chem. 1996 Jun 7;271(23):13829-33. doi: 10.1074/jbc.271.23.13829.
The construction, expression, and purification of an active Fv fragment of the 0.5beta monoclonal human immunodeficiency virus type 1 (HIV-1) neutralizing antibody is reported. The interaction between the Fv fragment and the RP135 peptide derived from the V3 loop of gp120 from HIV-1IIIB was studied by varying the salt concentration and by mutating arginine residues in the peptide. The mutations R4A, R8A and R11A (which correspond to residues 311, 315, and 318 in gp120 of HIV-1IIIB) reduce the binding free energy by 0.22 (+/- 0. 20), 4.32 (+/- 0.16), and 1.58 (+/- 0.17) kcal mol-1, respectively. The salt-dependent components of their contributions to binding are 0.02 (+/- 0.22), -0.55 (+/- 0.18), and -0.97 (+/- 0.19) kcal mol-1, respectively. The magnitudes of the mutational effects and the extent of shielding by 1 M NaCl suggest that Arg-8 is involved in a buried salt bridge in the peptide-Fv fragment complex, whereas Arg-11 is involved in a more solvent-exposed electrostatic interaction.
报道了1型人类免疫缺陷病毒（HIV-1）0.5β单克隆中和抗体活性Fv片段的构建、表达及纯化。通过改变盐浓度以及对源自HIV-1IIIB型gp120 V3环的RP135肽中的精氨酸残基进行突变，研究了Fv片段与该肽之间的相互作用。R4A、R8A和R11A突变（分别对应于HIV-1IIIB型gp120中的311、315和318位残基）使结合自由能分别降低0.22（±0.20）、4.32（±0.16）和1.58（±0.17）kcal mol-1。它们对结合贡献的盐依赖性成分分别为0.02（±0.22）、-0.55（±0.18）和-0.97（±0.19）kcal mol-1。突变效应的大小以及1 M NaCl的屏蔽程度表明，Arg-8参与了肽-Fv片段复合物中一个埋藏的盐桥，而Arg-11参与了一个更多暴露于溶剂中的静电相互作用。
