Structural basis for Sfm1 functioning as a protein arginine methyltransferase.
Lv, F., Zhang, T., Zhou, Z., Gao, S., Wong, C.C., Zhou, J.Q., Ding, J.(2015) Cell Discov 1: 15037-15037
- PubMed: 27462434 
- DOI: https://doi.org/10.1038/celldisc.2015.37
- Primary Citation of Related Structures:  
5C74, 5C77 - PubMed 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.
Organizational 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.