Methylation of the polyomavirus major capsid protein VP1

Polyomavirus VP1 has been shown to be modified by phosphorylation, sulfation, acetylation and hydroxylation. The major capsid protein VP1 is now shown to be modified by methylation. Addition of cycloheximide to infected cultures followed by addition of [H-3-methyl]-L-methionine and subsequent immunoprecipitation, SDS-PAGE and fluorography revealed methylation occurring on VP1. Amino acid analysis of [H-3-methyl]-L-methionine-labelled polyomavirus VP1 by two-dimensional paper chromatography and HPLC of the acid-hydrolyzed protein revealed the presence of H-3-labelled trimethyllysine and monomethylarginine.