MT-MAMS: protein methyltransferase motif analysis by mass spectrometry

Protein methyltransferases can recognise their substrates through linear sequence motifs and determination of these motifs is critical to understand methyltransferase mechanism, function and drug targeting. Here we describe MT-MAMS (methyltransferase motif analysis by mass spectrometry), a quantitative approach to characterise methyltransferase substrate recognition motifs and enzyme processivity. We validated MT-MAMS by application to lysine methyltransferase G9a, then determined the recognition motifs of Efm1 and major arginine methyltransferases Hmt1 and PRMT1.