Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2021 Aug 5;49(15):8822–8835. doi: 10.1093/nar/gkab677

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© The Author(s) 2021. Published by Oxford University Press on behalf of Nucleic Acids Research.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

PMC Copyright notice

Figure 3. — Removal of the GMP moiety in the presence of pyrophosphate. (A) Top: Pyrophosphorolysis of the nascent product RNA (pRNA; red). The active site (marked by the position of the catalytic Mg²⁺; magenta sphere) consists of two sub-sites: the P-site (product; yellow) and the A-site (acceptor; cyan). Following nucleotide addition, the pRNA 3′ end is bound in the A-site in the pre-translocated state. Upon forward translocation, the 3′ end moves to the P-site and the incoming substrate NTP (blue) can bind to the A-site through base pairing with the acceptor base of the RNA template strand (black). The pre-translocated state is sensitive to pyrophosphorolysis, which generates the NTP product and a one-nt shortened pRNA. Bottom: SARS-CoV-2 RdRp transcription complex assembled on the 5′ Cy5.5-labeled hairpin, which comprises both the template and the product RNAs, is completely resistant to PP_i even in the absence of NTPs. (B) GMP removal from nsp9 in the presence of PP_i. (C) The hand-over assay in which pre-GMPylated nsp9 is incubated with WT or mutant nsp12 variants. Signal intensity was compared to that observed with nsp9 incubated with buffer (set at 1) and is shown as mean ± SD (n = 3).