Măgureanu C G, Diaconu C, Alexandrescu R, Tirdei G, Cernescu C
Stefan S. Nicolau Institute of Virology, Bucharest, Romania.
Rev Roum Virol. 1994 Jul-Dec;45(3-4):143-57.
The nature of physical forces responsible for the antibody-antigen (Ab-Ag) reaction was analyzed in an original system, represented by synthetic peptides derived from the V3 consensus sequences of some HIV1 subtypes gp 120 and HIV1 positive human serum. For locating antigenic determines, flexibility, hydrophilicity and hydrophobicity profiles of the V3 peptides were analysed. The hydrophilicity indicates that V3 apex borders are involved in the first stage of the reaction. The flexibility and hydrophobicity suggest that the apex of the V3 loop (GPGR/Q) is involved in the stabilization of the complex by hydrophobic interactions. Further, we followed up the influence of the dielectric constant and of the pH upon the forces established between Ab and Ag. Modifications in the dielectric constant and pH reveal a significant contribution of electrostatic and van der Waals forces in securing the intermolecular complementarity. D2O produces the highest augmentation of the antibody affinity for the most hydrophilic peptides, while a very slight one was recorded for the most hydrophobic sequence. A high affinity of antibodies for the peptides MN, R and Z was registered at an acid pH, when their His residue was protonated. On the contrary, no influence was recorded in the case of the peptide A, which does not contain any His residue.
在一个原始系统中分析了负责抗体 - 抗原（Ab - Ag）反应的物理力的性质，该系统由源自某些HIV - 1亚型gp120的V3共有序列的合成肽和HIV - 1阳性人血清代表。为了定位抗原决定簇，分析了V3肽的柔韧性、亲水性和疏水性概况。亲水性表明V3顶端边界参与反应的第一阶段。柔韧性和疏水性表明V3环（GPGR/Q）的顶端通过疏水相互作用参与复合物的稳定。此外，我们跟踪了介电常数和pH对Ab和Ag之间建立的力的影响。介电常数和pH的变化揭示了静电和范德华力在确保分子间互补性方面的重要贡献。D2O对最亲水的肽产生最高的抗体亲和力增强，而对最疏水的序列记录到非常轻微的增强。当肽MN、R和Z的His残基质子化时，在酸性pH下记录到抗体对它们的高亲和力。相反，对于不包含任何His残基的肽A，未记录到影响。
