title: Bioorthogonal profiling of protein methylation using azido derivative of S-adenosyl-L-methionine.
abstract: Protein methyltransferases (PMTs) play critical roles in multiple biological processes. Because PMTs often function in vivo through forming multimeric protein complexes, dissecting their activities in the native contexts is challenging but relevant. To address such a need, we envisioned a Bioorthogonal Profiling of Protein Methylation (BPPM) technology, in which a SAM analogue cofactor can be utilized by multiple rationally engineered PMTs to label substrates of the corresponding native PMTs. Here, 4-azidobut-2-enyl derivative of S-adenosyl-L-methionine (Ab-SAM) was reported as a suitable BPPM cofactor. The resultant cofactor-enzyme pairs were implemented to label specifically the substrates of closely related PMTs (e.g., EuHMT1 and EuHMT2) in a complex cellular mixture. The BPPM approach, coupled with mass spectrometric analysis, enables the identification of the nonhistone targets of EuHMT1/2. Comparison of EuHMT1/2's methylomes indicates that the two human PMTs, although similar in terms of their primary sequences, can act on the distinct sets of nonhistone targets. Given the conserved active sites of PMTs, Ab-SAM and its use in BPPM are expected to be transferable to other PMTs for target identification.
authors.affiliation: Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA.
authors.forename: Kabirul
authors.initials: K
authors.lastname: Islam
authors.forename: Ian
authors.initials: I
authors.lastname: Bothwell
authors.forename: Yuling
authors.initials: Y
authors.lastname: Chen
authors.forename: Caitlin
authors.initials: C
authors.lastname: Sengelaub
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.forename: Haiteng
authors.initials: H
authors.lastname: Deng
authors.forename: Minkui
authors.initials: M
authors.lastname: Luo
mesh_terms: D001386:Azides / Q000737:chemistry*; D057930:Click Chemistry; D003067:Coenzymes / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D008745:Methylation; D011496:Protein Methyltransferases / Q000737:chemistry* / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism; D015203:Reproducibility of Results; D012436:S-Adenosylmethionine / Q000737:chemistry* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D001386:Azides; D003067:Coenzymes; D020543:Proteome; D012436:S-Adenosylmethionine; D011496:Protein Methyltransferases