PDBsum entry 4hi3

Hydrolase

PDB id: 4hi3

Contents

Protein chains

300 a.a.

Waters ×266

PDB id:

4hi3

Name:

Hydrolase

Title:

Crystal structure of dimeric r298a mutant of sars coronavirus main protease

Structure:

3c-like proteinase. Chain: a, b. Synonym: 3cl-pro, 3clp. Engineered: yes. Mutation: yes

Source:

Sars coronavirus. Organism_taxid: 227859. Gene: 1a. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.09Å R-factor: 0.192 R-free: 0.241

Authors:

C.-G.Wu,C.-Y.Chou

Key ref:

C.G.Wu et al. (2013). Mechanism for controlling the monomer-dimer conversion of SARS coronavirus main protease. Acta Crystallogr D Biol Crystallogr, 69, 747-755. PubMed id: 23633583 DOI: 10.1107/S0907444913001315

Date:

11-Oct-12 Release date: 01-May-13

Protein chains

P0C6U8  (R1A_CVHSA) -  Replicase polyprotein 1a from Severe acute respiratory syndrome coronavirus

Seq: 4382 a.a.

Struc: 300 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class 1: E.C.2.7.7.50 - mRNA guanylyltransferase.
• Reaction: a 5'-end diphospho-ribonucleoside in mRNA + GTP + H⁺ = a 5'-end (5'-triphosphoguanosine)-ribonucleoside in mRNA + diphosphate
• Enzyme class 2: E.C.3.4.19.12 - ubiquitinyl hydrolase 1.
• Reaction: Thiol-dependent hydrolysis of ester, thiolester, amide, peptide and isopeptide bonds formed by the C-terminal Gly of ubiquitin (a 76-residue protein attached to proteins as an intracellular targeting signal).
• Enzyme class 3: E.C.3.4.22.- - ?????
• Enzyme class 4: E.C.3.4.22.69 - Sars coronavirus main proteinase.

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Added reference

DOI no: 10.1107/S0907444913001315

Acta Crystallogr D Biol Crystallogr 69:747-755 (2013)

PubMed id: 23633583

Mechanism for controlling the monomer-dimer conversion of SARS coronavirus main protease.

C.G.Wu, S.C.Cheng, S.C.Chen, J.Y.Li, Y.H.Fang, Y.H.Chen, C.Y.Chou.

ABSTRACT

The Severe acute respiratory syndrome coronavirus (SARS-CoV) main protease (M(pro)) cleaves two virion polyproteins (pp1a and pp1ab); this essential process represents an attractive target for the development of anti-SARS drugs. The functional unit of M(pro) is a homodimer and each subunit contains a His41/Cys145 catalytic dyad. Large amounts of biochemical and structural information are available on M(pro); nevertheless, the mechanism by which monomeric M(pro) is converted into a dimer during maturation still remains poorly understood. Previous studies have suggested that a C-terminal residue, Arg298, interacts with Ser123 of the other monomer in the dimer, and mutation of Arg298 results in a monomeric structure with a collapsed substrate-binding pocket. Interestingly, the R298A mutant of M(pro) shows a reversible substrate-induced dimerization that is essential for catalysis. Here, the conformational change that occurs during substrate-induced dimerization is delineated by X-ray crystallography. A dimer with a mutual orientation of the monomers that differs from that of the wild-type protease is present in the asymmetric unit. The presence of a complete substrate-binding pocket and oxyanion hole in both protomers suggests that they are both catalytically active, while the two domain IIIs show minor reorganization. This structural information offers valuable insights into the molecular mechanism associated with substrate-induced dimerization and has important implications with respect to the maturation of the enzyme.