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A flexible cofactor‐binding loop in the novel arginine methyltransferase Sfm1
Author(s) -
Wang Caiyan,
Zeng Jianhua,
Xie Wei
Publication year - 2017
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1002/1873-3468.12533
Subject(s) - methyltransferase , methylation , arginine , protein arginine methyltransferase 5 , cocrystal , biochemistry , transfer rna , chemistry , cofactor , transferase , enzyme , rna , stereochemistry , biology , amino acid , dna , molecule , hydrogen bond , organic chemistry , gene
Arginine methylation is a common post‐translational modification and is critical for many cellular processes. Sfm1 is a novel arginine methyltransferase that contains a SpoU‐TrmD ( SPOUT ) domain, a typical fold known for RNA methylation, but acts on a ribosomal protein. The underlying mechanism is poorly understood. Here, we report cocrystal structures of Sfm1 in complex with various ligands. We found that a critical loop responsible for S ‐adenosyl‐ l ‐methionine ( SAM ) binding adopts a different conformation from previous reports, and SAM appears to exhibit double conformations. Deletion of this loop greatly reduces the affinity of Sfm1 to SAM . Additionally, by comparison to closely related tRNA ‐methyltransferase Trm10, our structural analyses offer a good explanation why the two enzymes utilize distinct substrates, providing insights into the molecular mechanism.