Structural highlights
Function
[K4LC41_9BETC] Nsp7-nsp8 hexadecamer may possibly confer processivity to the polymerase, maybe by binding to dsRNA or by producing primers utilized by the latter (By similarity).[SAAS:SAAS014829_004_014545] Nsp9 is a ssRNA-binding protein (By similarity).[SAAS:SAAS014829_004_001449]
Publication Abstract from PubMed
The Middle East Respiratory Syndrome coronavirus (MERS-CoV) papain-like protease (PLpro) blocking loop 2 (BL2) structure differs significantly from that of SARS-CoV PLpro, where it has been proven to play a crucial role in SARS-CoV PLpro inhibitor binding. Four SARS-CoV PLpro lead inhibitors were tested against MERS-CoV PLpro, none of which were effective against MERS-CoV PLpro. Structure and sequence alignments revealed that two residues, Y269 and Q270, responsible for inhibitor binding to SARS-CoV PLpro, were replaced by T274 and A275 in MERS-CoV PLpro, making critical binding interactions difficult to form for similar types of inhibitors. High-throughput screening (HTS) of 25000 compounds against both PLpro enzymes identified a small fragment-like noncovalent dual inhibitor. Mode of inhibition studies by enzyme kinetics and competition surface plasmon resonance (SPR) analyses suggested that this compound acts as a competitive inhibitor with an IC50 of 6 muM against MERS-CoV PLpro, indicating that it binds to the active site, whereas it acts as an allosteric inhibitor against SARS-CoV PLpro with an IC50 of 11 muM. These results raised the possibility that inhibitor recognition specificity of MERS-CoV PLpro may differ from that of SARS-CoV PLpro. In addition, inhibitory activity of this compound was selective for SARS-CoV and MERS-CoV PLpro enzymes over two human homologues, the ubiquitin C-terminal hydrolases 1 and 3 (hUCH-L1 and hUCH-L3).
Inhibitor Recognition Specificity of MERS-CoV Papain-like Protease May Differ from That of SARS-CoV.,Lee H, Lei H, Santarsiero BD, Gatuz JL, Cao S, Rice AJ, Patel K, Szypulinski MZ, Ojeda I, Ghosh AK, Johnson ME ACS Chem Biol. 2015 Mar 16. PMID:25746232[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Lee H, Lei H, Santarsiero BD, Gatuz JL, Cao S, Rice AJ, Patel K, Szypulinski MZ, Ojeda I, Ghosh AK, Johnson ME. Inhibitor Recognition Specificity of MERS-CoV Papain-like Protease May Differ from That of SARS-CoV. ACS Chem Biol. 2015 Mar 16. PMID:25746232 doi:http://dx.doi.org/10.1021/cb500917m