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bioRxiv · 10.1101/2021.09.10.459800

pH-dependent polymorphism of the structure of SARS-CoV-2 nsp7

Lee, Y.·Tonelli, M.·Rahimi, M.·Anderson, T. K.·Kirchdoerfer, R. N.·Henzler-Wildman, K.·Lee, W.
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Abstract

The solution structure of SARS-CoV-2 nonstructural protein 7 (nsp7) at pH 7.0 has been determined by NMR spectroscopy. nsp7 is conserved in the coronavirinae subfamily and is an essential co-factor of the viral RNA-dependent RNA polymerase for active and processive replication. Similar to the previously deposited structures of SARS-CoV-1 nsp7 at acidic and basic conditions, SARS-CoV-2 nsp7 has a helical bundle folding at neutral pH. Remarkably, the 4 helix shows gradual dislocation from the core 2-3 structure as pH increases from 6.5 to 7.5. The protonation state of residue H36 contributes to the change of nsp7s intramolecular interactions, and thus, to the structural variation near-neutral pH. Spin-relaxation results revealed that all three loop regions in nsp7 possess dynamic properties associated with this structural variation.

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Lee, Y., Tonelli, M., Rahimi, M., Anderson, T. K., Kirchdoerfer, R. N., Henzler-Wildman, K., Lee, W.. 2021-09-10. pH-dependent polymorphism of the structure of SARS-CoV-2 nsp7. https://doi.org/10.1101/2021.09.10.459800

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