Critical Assessment of the Important Residues Involved in the Dimerization and Catalysis of MERS Coronavirus Main Protease

Abstract

BackgroundA highly pathogenic human coronavirus (CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), has emerged in Jeddah and other places in Saudi Arabia, and has quickly spread to European and Asian countries since September 2012. Up to the 1st October 2015 it has infected at least 1593 people with a global fatality rate of about 35%. Studies to understand the virus are necessary and urgent. In the present study, MERS-CoV main protease (Mpro) is expressed; the dimerization of the protein and its relationship to catalysis are investigated.Methods and ResultsThe crystal structure of MERS-CoV Mpro indicates that it shares a similar scaffold to that of other coronaviral Mpro and consists of chymotrypsin-like domains I and II and a helical domain III of five helices. Analytical ultracentrifugation analysis demonstrated that MERS-CoV Mpro undergoes a monomer to dimer conversion in the presence of a peptide substrate. Glu169 is a key residue and plays a dual role in both dimerization and catalysis. The mutagenesis of other residues found on the dimerization interface indicate that dimerization of MERS-CoV Mpro is required for its catalytic activity. One mutation, M298R, resulted in a stable dimer with a higher level of proteolytic activity than the wild-type enzyme.ConclusionsMERS-CoV Mpro shows substrate-induced dimerization and potent proteolytic activity. A critical assessment of the residues important to these processes provides insights into the correlation between dimerization and catalysis within the coronaviral Mpro family.

Identification and evaluation of potent Middle East respiratory syndrome coronavirus (MERS-CoV) 3CL Pro inhibitors

“…The amide group between phenylalanine and cinnamoyl group further forms H-bonds with Gln192 and Glu169. We also docked 6d based on the apo-form MERS-CoV 3CL pro structure (PDB code: 5c3n) (Ho et al, 2015). Since the free-form and ligand-bound structures showed no significant difference in the active site, the binding modes of 6d in these two structures are indeed very similar (data not shown).…”

Dynamics of scientific publications on the MERS-CoV outbreaks in Saudi Arabia

“…However, MERS-CoV has a high morbidity and case-fatality rate, particularly among ICU and/or critically ill patients, those with comorbid illness, older patients and those with a high viral load [11,12,15,[92][93][94]. The potential for viral mutations, for example in the viral spike (S) protein, which mediates viral entry into host cells, or in viral proteases such as Mpro, could increase viral affinity for human host cells and expand host cell range [50,[94][95][96]. Thus, surveillance, contact tracing and research into possible animal hosts and transmission pathways to humans need to be prioritized [37].…”

A review of candidate therapies for Middle East respiratory syndrome from a molecular perspective

“…The availability of host cell proteases is essential for MERS-CoV entry into cells [23,53]. The host proteases responsible for S protein cleavage at the S1/S2 boundary include the serine protease TMPRSS2, endosomal cathepsins such as cathepsin L, and furin protease [23,53,[59][60][61]. In vitro studies suggest that uncleaved MERS pseudovirus can enter host cells by cathepsin L-dependent endocytosis, but that cleavage of virus during maturation by host proteases such as TMPRSS2 results in viral entry at neutral pH and the formation of massive syncytia [58].…”