The properties of HIV protease synthesized in E. coli cells

A hybrid plasmid pPR6 was constructed containing BgII-EcoRI fragment of the pol region of HIV (strain IIIB) genome which determined the synthesis of virus-specific protease. Extracts of E. coli DN5/pPR6 bacteria provided for specific hydrolysis of hybrid protein p165 (the N-terminus of which is presented by complete beta-galactosidase and the C-terminus by duplicated area of virus-specific precursor p55 containing a site for virus-specific protease located at the border of proteins p17 and p24) with formation of products having molecular weights of 19, 42, 28, 23, and 19 kD. Polypeptides 119K, 23K, and 19K are products of complete hydrolysis, and 42K a result of partial cleavage. The kinetics of hydrolysis in relation to pH values of the reaction mixture was analysed. It is suggested that the reported system of HIV protease activity determination be used for screening of potential inhibitors of this enzyme.