Mechanistic studies on transcriptional coactivator protein arginine methyltransferase 1
UMass Chan Affiliations
Department of Biochemistry and Molecular PharmacologyDocument Type
Journal ArticlePublication Date
2011-04-26Keywords
CatalysisCatalytic Domain
Guanidine
Mutagenesis, Site-Directed
Protein-Arginine N-Methyltransferases
S-Adenosylmethionine
Substrate Specificity
Biochemistry
Enzymes and Coenzymes
Medicinal-Pharmaceutical Chemistry
Therapeutics
Metadata
Show full item recordAbstract
Protein arginine methyltransferases (PRMTs) catalyze the transfer of methyl groups from S-adenosylmethionine (SAM) to the guanidinium group of arginine residues in a number of important cell signaling proteins. PRMT1 is the founding member of this family, and its activity appears to be dysregulated in heart disease and cancer. To begin to characterize the catalytic mechanism of this isozyme, we assessed the effects of mutating a number of highly conserved active site residues (i.e., Y39, R54, E100, E144, E153, M155, and H293), which are believed to play key roles in SAM recognition, substrate binding, and catalysis. The results of these studies, as well as pH-rate studies, and the determination of solvent isotope effects (SIEs) indicate that M155 plays a critical role in both SAM binding and the processivity of the reaction but is not responsible for the regiospecific formation of asymmetrically dimethylated arginine (ADMA). Additionally, mutagenesis studies on H293, combined with pH studies and the lack of a normal SIE, do not support a role for this residue as a general base. Furthermore, the lack of a normal SIE with either the wild type or catalytically impaired mutants suggests that general acid/base catalysis is not important for promoting methyl transfer. This result, combined with the fact that the E144A/E153A double mutant retains considerably more activity then the single mutants alone, suggests that the PRMT1-catalyzed reaction is primarily driven by bringing the substrate guanidinium into the proximity of the S-methyl group of SAM and that the prior deprotonation of the substrate guanidinium is not required for methyl transfer.Source
Biochemistry. 2011 Apr 26;50(16):3332-45. doi: 10.1021/bi102022e. Link to article on publisher's site. Epub 2011 Apr 1.DOI
10.1021/bi102022ePermanent Link to this Item
http://hdl.handle.net/20.500.14038/50044Notes
At the time of publication, Paul Thompson was not yet affiliated with UMass Medical School.
Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1021/bi102022e