title: Protein Arginine Methyltransferase Product Specificity Is Mediated by Distinct Active-site Architectures.
abstract: In the family of protein arginine methyltransferases (PRMTs) that predominantly generate either asymmetric or symmetric dimethylarginine (SDMA), PRMT7 is unique in producing solely monomethylarginine (MMA) products. The type of methylation on histones and other proteins dictates changes in gene expression, and numerous studies have linked altered profiles of methyl marks with disease phenotypes. Given the importance of specific inhibitor development, it is crucial to understand the mechanisms by which PRMT product specificity is conferred. We have focused our attention on active-site residues of PRMT7 from the protozoan Trypanosoma brucei We have designed 26 single and double mutations in the active site, including residues in the Glu-Xaa8-Glu (double E) loop and the Met-Gln-Trp sequence of the canonical Thr-His-Trp (THW) loop known to interact with the methyl-accepting substrate arginine. Analysis of the reaction products by high resolution cation exchange chromatography combined with the knowledge of PRMT crystal structures suggests a model where the size of two distinct subregions in the active site determines PRMT7 product specificity. A dual mutation of Glu-181 to Asp in the double E loop and Gln-329 to Ala in the canonical THW loop enables the enzyme to produce SDMA. Consistent with our model, the mutation of Cys-431 to His in the THW loop of human PRMT9 shifts its product specificity from SDMA toward MMA. Together with previous results, these findings provide a structural basis and a general model for product specificity in PRMTs, which will be useful for the rational design of specific PRMT inhibitors.
authors.affiliation: From the Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, Los Angeles, California 90095 and.
authors.forename: Kanishk
authors.initials: K
authors.lastname: Jain
authors.affiliation: From the Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, Los Angeles, California 90095 and.
authors.forename: Rebeccah A
authors.initials: RA
authors.lastname: Warmack
authors.affiliation: the Laboratory of Cell Biology and.
authors.forename: Erik W
authors.identifier: 0000-0002-2587-2150
authors.initials: EW
authors.lastname: Debler
authors.affiliation: From the Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, Los Angeles, California 90095 and.
authors.forename: Andrea
authors.identifier: 0000-0002-3420-367X
authors.initials: A
authors.lastname: Hadjikyriacou
authors.affiliation: the Laboratory of Cell Biology and Laboratory of Lymphocyte Biology, The Rockefeller University, New York, New York 10065.
authors.forename: Peter
authors.initials: P
authors.lastname: Stavropoulos
authors.affiliation: From the Department of Chemistry and Biochemistry and the Molecular Biology Institute, UCLA, Los Angeles, California 90095 and clarke@mbi.ucla.edu.
authors.forename: Steven G
authors.identifier: 0000-0002-7303-6632
authors.initials: SG
authors.lastname: Clarke
mesh_terms: D019943:Amino Acid Substitution; D001120:Arginine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020134:Catalytic Domain; D006801:Humans; D020125:Mutation, Missense; D017433:Protein Structure, Secondary; D011484:Protein-Arginine N-Methyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity / Q000235:genetics; D014346:Trypanosoma brucei brucei / Q000201:enzymology* / Q000235:genetics
chemical_list: D015800:Protozoan Proteins; D001120:Arginine; D011484:Protein-Arginine N-Methyltransferases
keywords: PRMT; PRMT product specificity; enzyme catalysis; epigenetics; histone methylation; methyltransferase; post-translational modification (PTM); protein arginine methylation; protein methylation