The interaction between the non-structural proteins nsp16 an...

created [InstanceEdit:9694660] Cook, Justin, 2020-07-07
dbId 9694673
displayName The interaction between the non-structural proteins nsp16 an...
literatureReference
modified [InstanceEdit:9762825] Stephan, Ralf, 2022-01-28
schemaClass Summation
text The interaction between the non-structural proteins nsp16 and nsp10 is conserved in SARS-CoV-2 virus (Li et al. 2020, Viswanathan et al. 2020, Rosas-Lemus et al. 2020; Xu et al, 2021).

In SARS-CoV-1, nsp16 was identified as an AdoMet-dependent (nucleoside-2'O)-methyltransferase involved in capping of viral RNAs. nsp16 binds to nsp10, which serves as a cofactor for nsp16 (Bouvet et al. 2010, Lugari et al. 2010). nsp16 alone is unstable and exhibits 2'-O-methyltransferase activity only in complex with nsp10 (Debarnot et al, 2011; Decroly et al, 2011). nsp10-mediated activation of nsp16 catalytic activity is conserved in all coronaviruses (Wang et al. 2015). The same binding surface of nsp10 interacts with nsp14 and nsp16, suggesting that binding of nsp14 and nsp16 to nsp10 is mutually exclusive. However, as nsp10 is produced in a higher number of copies than nsp14 and nsp16, and as nsp14 and nsp16 act coordinately in RNA capping, it is most likely that nsp14:nsp10 and nsp16:nsp10 complexes co-exist within the viral replication-transcription complex (RTC) (Bouvet et al. 2012, Bouvet et al. 2014). One structural study reported that nsp10 forms dodecamers (Su et al. 2006), which would potentially allow simultaneous binding of nsp14 and nsp16 to nsp10 homomeric complexes, but it is not certain if such homomeric complexes of nsp10 exist in vivo, and if the structure of the nsp10 dodecamer would be permissive for nsp16 binding (Chen et al. 2011). nsp10 contains two zinc fingers which are thought to be involved in RNA binding (Su et al. 2006, Joseph et al. 2006). For efficient 2'-O-methyltransferase activity, two metal ions are bound by the complex. Both Mg2+ and Mn2+ show similarly optimal cofactor activities in vitro (Minasov et al, 2021).
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