title: Mutation of Gly-11 on the dimer interface results in the complete crystallographic dimer dissociation of severe acute respiratory syndrome coronavirus 3C-like protease: crystal structure with molecular dynamics simulations.
abstract: SARS-CoV 3C-like protease (3CL(pro)) is an attractive target for anti-severe acute respiratory syndrome (SARS) drug discovery, and its dimerization has been extensively proved to be indispensable for enzymatic activity. However, the reason why the dissociated monomer is inactive still remains unclear due to the absence of the monomer structure. In this study, we showed that mutation of the dimer-interface residue Gly-11 to alanine entirely abolished the activity of SARS-CoV 3CL(pro). Subsequently, we determined the crystal structure of this mutant and discovered a complete crystallographic dimer dissociation of SARS-CoV 3CL(pro). The mutation might shorten the alpha-helix A' of domain I and cause a mis-oriented N-terminal finger that could not correctly squeeze into the pocket of another monomer during dimerization, thus destabilizing the dimer structure. Several structural features essential for catalysis and substrate recognition are severely impaired in the G11A monomer. Moreover, domain III rotates dramatically against the chymotrypsin fold compared with the dimer, from which we proposed a putative dimerization model for SARS-CoV 3CL(pro). As the first reported monomer structure for SARS-CoV 3CL(pro), the crystal structure of G11A mutant might provide insight into the dimerization mechanism of the protease and supply direct structural evidence for the incompetence of the dissociated monomer.
authors.affiliation: Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai 201203 China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Chen
authors.affiliation: Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai 201203 China.
authors.forename: Tiancen
authors.initials: T
authors.lastname: Hu
authors.affiliation: Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai 201203 China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai 201203 China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai 201203 China.
authors.forename: Kaixian
authors.initials: K
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Ding
authors.affiliation: Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai 201203 China. Electronic address: hljiang@mail.shcnc.ac.cn.
authors.forename: Hualiang
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai 201203 China. Electronic address: xshen@mail.shcnc.ac.cn.
authors.forename: Xu
authors.initials: X
authors.lastname: Shen
mesh_terms: D002942:Circular Dichroism; D003198:Computer Simulation; D000086782:Coronavirus 3C Proteases; D018360:Crystallography, X-Ray; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D005998:Glycine / Q000235:genetics*; D008958:Models, Molecular; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D045473:Severe acute respiratory syndrome-related coronavirus / Q000201:enzymology*; D013050:Spectrometry, Fluorescence; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D014764:Viral Proteins; D003546:Cysteine Endopeptidases; D000086782:Coronavirus 3C Proteases; D005998:Glycine