Mechanisms leading to an oriented immobilization of recombinant proteins derived from the p24 capsid of HIV-1 onto copolymers

To investigate the mechanism leading to an oriented immobilization of recom binant proteins onto synthetic copolymers, five genetically modified HIV-1 p24 capsid proteins (RH24, RH24A(4)K(2), RH24R(6), RH24R(4)K(2), and RH24K( 6)) were tested for their efficiency to covalently bind to maleic. anhydrid e-alt-methyl vinyl ether (MAMVE) and N-vinyl pyrrolidone-alt-maleic anhydri de (NVPMA) copolymers. These proteins contain, at their C-termini, tags dif fering in cationic and/or reactive amino acids density. We demonstrated tha t an increase of the charge and amine density in the tag enhances the coupl ing yield, the most efficient tag being a six lysine one. The reactivity of the proteins depends directly on the reactivity of the tag, and this led u s to conclude that the tag was the site where the covalent grafting with th e polymer occurred. Thus, design of such tags provides a new efficient and versatile method allowing oriented immobilization of recombinant proteins o nto copolymers.