3q7e | pdb_00003q7e
Crystal Structure of rat Protein Arginine Methyltransferase 1 (PRMT1)M48L mutant
Structural highlights
FunctionANM1_RAT Arginine methyltransferase that methylates (mono and asymmetric dimethylation) the guanidino nitrogens of arginyl residues present in proteins such as ESR1, histone H2, H3 and H4, PIAS1, HNRNPA1, HNRNPD, NFATC2IP, SUPT5H, TAF15 and EWS. Constitutes the main enzyme that mediates monomethylation and asymmetric dimethylation of histone H4 'Arg-4' (H4R3me1 and H4R3me2a, respectively), a specific tag for epigenetic transcriptional activation. Together with dimethylated PIAS1, represses STAT1 transcriptional activity, in the late phase of interferon gamma (IFN-gamma) signaling. May be involved in the regulation of TAF15 transcriptional activity, act as an activator of estrogen receptor (ER)-mediated transactivation, play a key role in neurite outgrowth and act as a negative regulator of megakaryocytic differentiation, by modulating p38 MAPK pathway.[1] [2] [3] Publication Abstract from PubMedProtein-arginine methyltransferases aid in the regulation of many biological processes by methylating specific arginyl groups within targeted proteins. The varied nature of the response to methylation is due in part to the diverse product specificity displayed by the protein-arginine methyltransferases. In addition to site location within a protein, biological response is also determined by the degree (mono-/dimethylation) and type of arginine dimethylation (asymmetric/symmetric). Here, we have identified two strictly conserved methionine residues in the PRMT1 active site that are not only important for activity but also control substrate specificity. Mutation of Met-155 or Met-48 results in a loss in activity and a change in distribution of mono- and dimethylated products. The altered substrate specificity of M155A and M48L mutants is also evidenced by automethylation. Investigation into the mechanistic basis of altered substrate recognition led us to consider each methyl transfer step separately. Single turnover experiments reveal that the rate of transfer of the second methyl group is much slower than transfer of the first methyl group in M48L, especially for arginine residues located in the center of the peptide substrate where turnover of the monomethylated species is negligible. Thus, altered product specificity in M48L originates from the differential effect of the mutation on the two rates. Characterization of the two active-site methionines provides the first insight into how the PRMT1 active site is engineered to control product specificity. Investigation of the molecular origins of protein-arginine methyltransferase I (PRMT1) product specificity reveals a role for two conserved methionine residues.,Gui S, Wooderchak WL, Daly MP, Porter PJ, Johnson SJ, Hevel JM J Biol Chem. 2011 Aug 19;286(33):29118-26. Epub 2011 Jun 21. PMID:21697082[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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