Chemical crosslinking of proteins in avian sarcoma and leukemia viruses

Abstract

We have investigated the nearest neighbor relationships of proteins in avian sarcoma and leukemia viruses by means of bifunctional crosslinking agents. In intact virions dimethyl suberimidate and dithiobispropionimidate induce the formation of covalently linked multimeric species of all four internal structural proteins ( gag proteins). By immunological tests and by two-dimensional polyacrylamide gel electrophoresis the major species were identified as homotypic dimers of p27, p19, p15, and p12, and homotypic tetramers of p27. No recognizable heterotypic multimers of gag proteins are formed. We conclude that the major gag protein-protein interactions in virions occur between like species. The crosslinking agents also introduce links into the env protein dimer, gp85-gp37, and form a higher multimer of this dimer.