title: Structure-function analysis of severe acute respiratory syndrome coronavirus RNA cap guanine-N7-methyltransferase.
abstract: Coronaviruses possess a cap structure at the 5' ends of viral genomic RNA and subgenomic RNAs, which is generated through consecutive methylations by virally encoded guanine-N7-methyltransferase (N7-MTase) and 2'-O-methyltransferase (2'-O-MTase). The coronaviral N7-MTase is unique for its physical linkage with an exoribonuclease (ExoN) harbored in nonstructural protein 14 (nsp14) of coronaviruses. In this study, the structure-function relationships of the N7-MTase were analyzed by deletion and site-directed mutagenesis of severe acute respiratory syndrome coronavirus (SARS-CoV) nsp14. The results showed that the ExoN domain is closely involved in the activity of the N7-MTase, suggesting that coronavirus N7-MTase is different from all other viral N7-MTases, which are separable from other structural domains located in the same polypeptide. Two of the 12 critical residues identified to be essential for the N7-MTase were located at the N terminus of the core ExoN domain, reinforcing a role of the ExoN domain in the N7-MTase activity of nsp14. The other 10 critical residues were distributed throughout the N7-MTase domain but localized mainly in the S-adenosyl-l-methionine (SAM)-binding pocket and key structural elements of the MTase fold of nsp14. The sequence motif DxGxPxA (amino acids [aa] 331 to 338) was identified as the key part of the SAM-binding site. These results provide insights into the structure and functional mechanisms of coronaviral nsp14 N7-MTase.
authors.affiliation: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.forename: Jiali
authors.initials: J
authors.lastname: Tao
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.forename: Andong
authors.initials: A
authors.lastname: Wu
authors.forename: Ceyang
authors.initials: C
authors.lastname: Su
authors.forename: Guozhen
authors.initials: G
authors.lastname: Gao
authors.forename: Hui
authors.initials: H
authors.lastname: Cai
authors.forename: Su
authors.initials: S
authors.lastname: Qiu
authors.forename: Yingliang
authors.initials: Y
authors.lastname: Wu
authors.forename: Tero
authors.initials: T
authors.lastname: Ahola
authors.forename: Deyin
authors.initials: D
authors.lastname: Guo
mesh_terms: D005095:Exoribonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008745:Methylation; D008780:Methyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012315:RNA Caps / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D045473:Severe acute respiratory syndrome-related coronavirus / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D045169:Severe Acute Respiratory Syndrome / Q000821:virology*; D017361:Viral Nonstructural Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D012315:RNA Caps; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; D014764:Viral Proteins; D008780:Methyltransferases; C525596:nsp14 protein, SARS coronavirus; D005095:Exoribonucleases
references.citation: PLoS Pathog. 2005 Dec;1(4):e39
references.pmid: 16341254
references.citation: J Virol. 2004 Jun;78(11):5619-32
references.pmid: 15140959
references.citation: J Virol. 2006 Sep;80(17):8362-70
references.pmid: 16912287
references.citation: BMC Struct Biol. 2005 Oct 14;5:19
references.pmid: 16225687
references.citation: J Biol Chem. 2002 Dec 20;277(51):50155-9
references.pmid: 12364334
references.citation: Virus Res. 2006 Apr;117(1):17-37
references.pmid: 16503362
references.citation: Antiviral Res. 2012 Oct;96(1):21-31
references.pmid: 22841701
references.citation: Cell. 2003 Jun 13;113(6):701-2
references.pmid: 12809601
references.citation: PLoS Pathog. 2011 Oct;7(10):e1002294
references.pmid: 22022266
references.citation: EMBO J. 2002 Dec 2;21(23):6571-80
references.pmid: 12456663
references.citation: J Biochem Mol Biol. 2007 Sep 30;40(5):649-55
references.pmid: 17927896
references.citation: J Virol. 2007 Apr;81(8):3891-903
references.pmid: 17267492
references.citation: Nat Rev Mol Cell Biol. 2002 Aug;3(8):619-25
references.pmid: 12154373
references.citation: J Biol Chem. 1999 Jun 4;274(23):16553-62
references.pmid: 10347220
references.citation: J Mol Biol. 2003 Aug 29;331(5):991-1004
references.pmid: 12927536
references.citation: J Virol. 2005 Mar;79(6):3391-400
references.pmid: 15731233
references.citation: J Biol Chem. 2008 Jul 11;283(28):19410-21
references.pmid: 18469001
references.citation: J Biol Chem. 2002 Dec 20;277(51):50160-4
references.pmid: 12364333
references.citation: J Virol. 1981 May;38(2):661-70
references.pmid: 6165837
references.citation: Nat Immunol. 2011 Feb;12(2):137-43
references.pmid: 21217758
references.citation: Proc Natl Acad Sci U S A. 1995 Jan 17;92(2):507-11
references.pmid: 7831320
references.citation: N Engl J Med. 2003 May 15;348(20):1967-76
references.pmid: 12690091
references.citation: Nature. 2010 Nov 18;468(7322):452-6
references.pmid: 21085181
references.citation: Curr Opin Struct Biol. 2002 Dec;12(6):783-93
references.pmid: 12504684
references.citation: J Virol. 2007 Nov;81(22):12135-44
references.pmid: 17804504
references.citation: Proc Natl Acad Sci U S A. 2006 Mar 28;103(13):5108-13
references.pmid: 16549795
references.citation: J Virol. 1982 Feb;41(2):557-65
references.pmid: 6281467
references.citation: J Virol. 2010 Jul;84(14):7325-36
references.pmid: 20444893
references.citation: RNA. 2008 Apr;14(4):696-705
references.pmid: 18256245
references.citation: RNA. 2008 Nov;14(11):2297-304
references.pmid: 18799596
references.citation: J Virol. 1997 Jan;71(1):392-7
references.pmid: 8985362
references.citation: Adv Virus Res. 2000;55:135-84
references.pmid: 11050942
references.citation: EMBO J. 2007 Nov 28;26(23):4913-25
references.pmid: 17989694
references.citation: J Virol. 2008 Aug;82(16):8071-84
references.pmid: 18417574
references.citation: Proc Natl Acad Sci U S A. 2009 Mar 3;106(9):3484-9
references.pmid: 19208801
references.citation: PLoS Pathog. 2011 May;7(5):e1002059
references.pmid: 21637813
references.citation: PLoS Pathog. 2010 Apr 22;6(4):e1000863
references.pmid: 20421945
references.citation: Nat Rev Microbiol. 2011 Dec 05;10(1):51-65
references.pmid: 22138959
references.citation: J Virol. 2003 Jul;77(13):7300-7
references.pmid: 12805428
references.citation: Proc Natl Acad Sci U S A. 2006 May 30;103(22):8493-8
references.pmid: 16709677
references.citation: J Virol. 2005 May;79(9):5288-95
references.pmid: 15827143
references.citation: Trends Biochem Sci. 2004 Aug;29(8):436-44
references.pmid: 15362228
references.citation: Virology. 2006 Aug 15;352(1):145-56
references.pmid: 16716374
references.citation: Mol Cell. 2007 Jan 12;25(1):85-97
references.pmid: 17218273