title: Structural basis for Sfm1 functioning as a protein arginine methyltransferase.
abstract: SPOUT proteins constitute one class of methyltransferases, which so far are found to exert activity mainly towards RNAs. Previously, yeast Sfm1 was predicted to contain a SPOUT domain but can methylate ribosomal protein S3. Here we report the crystal structure of Sfm1, which comprises of a typical SPOUT domain and a small C-terminal domain. The active site is similar to that of protein arginine methyltransferases but different from that of RNA methyltransferases. In addition, Sfm1 exhibits a negatively charged surface surrounding the active site unsuitable for RNA binding. Our biochemical data show that Sfm1 exists as a monomer and has high activity towards ribosomal protein S3 but no activity towards RNA. It can specifically catalyze the methylation of Arg146 of S3 and the C-terminal domain is critical for substrate binding and activity. These results together provide the structural basis for Sfm1 functioning as a PRMT for ribosomal protein S3.
authors.affiliation: National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China.
authors.forename: Fengjuan
authors.initials: F
authors.lastname: Lv
authors.affiliation: National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China.
authors.forename: Tianlong
authors.initials: T
authors.lastname: Zhang
authors.affiliation: National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China.
authors.forename: Shuaixin
authors.initials: S
authors.lastname: Gao
authors.affiliation: National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China.
authors.forename: Catherine Cl
authors.initials: CC
authors.lastname: Wong
authors.affiliation: National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China.
authors.forename: Jin-Qiu
authors.initials: JQ
authors.lastname: Zhou
authors.affiliation: National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Ding
keywords: Arginine methylation; PRMT; SPOUT; ribosomal protein S3; ribosome assembly