LysargiNase mirrors trypsin for protein C-terminal and methylation-site identification

To improve proteome coverage and protein C-terminal identification, we characterized the Methanosarcina acetivorans thermophilic proteinase LysargiNase, which cleaves before lysine and arginine up to 55 °C. Unlike trypsin, LysargiNase-generated peptides had N-terminal lysine or arginine residues and fragmented with b ion-dominated spectra. This improved protein C terminal-peptide identification and several arginine-rich phosphosite assignments. Notably, cleavage also occurred at methylated or dimethylated lysine and arginine, facilitating detection of these epigenetic modifications.
The German Academic Exchange Service (DAAD) and the Michael Smith Foundation for Health Research (MSFHR) supported P.F.H. P.F.L. was supported by the Alexander von Humboldt Foundation, Breast Cancer Society of Canada and MSFHR; L.D.R. was supported by the Canadian Institutes for Health Research (CIHR) and MSFHR; and U.E. was supported by the MSFHR. This work was supported by a Canada Research Chair in Metalloproteinase Proteomics and Systems Biology (C.M.O.), a grant from the CIHR (grant number M.O.P. 111055) as well as by an Infrastructure Grant from MSFHR and the Canada Foundations for Innovation (C.M.O.). Further support was provided by the European Union FP7 program; Consolider Program of the Spanish Ministry of Science and Technology; and State Plan for Research in Science, Technology and Innovation of the Spanish Ministry of Economy and Competitiveness (F.X.G.-R.)