Abstract
Type Ⅳ protein arginine methyltransferase （RMT2） from the yeast Saccharomyces cerevisiae was expressed in Escherichia coli and purified by ion-exchange chromatography. The recombinant RMT2 at is apparently in monomeric form and has a molecular mass of 47 kDa as determined by gel exclusion chromatography. The recombinant protein was incubated with cell extracts from a wild type yeast strain then further separated on the Superose 6 column. RMT2 thus recovered has an elution volume suggesting the existence of a complex. The recovered recombinant RMT2 and the associated proteins were treated with DNase I and RNase A, and then further separated on the same column. The recombinant RMT2 still has the same retention time on the Superose 6 column. The putative RMT2 complex was purified from wild type yeast extracts with RMT2 specific antibodies coupled onto protein A-agarose beads. As controls, similar experiments were carried out with extracts from a RMT2 deletion strain. Proteins that are possibly associated or interacted with RMT2 were separated with 1-D SDS-PAGE and identified by peptide mapping on a time-of-flight mass spectrometer equipped with a MALDI source. Proteins identified include: Saa2p, Ssb1p, Cdc19p, Pdc1p, Tef2p, Eno2p, Pgk1p, Adh1p, Fba1p, Tdh3p and Tdh2p.