Fig. 5: Non-structural protein 16 (nsp16) protein-protein interaction with nsp7-11 polyprotein.
A The first mass spectrum shows severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nsp16-His6 (pink) mixed with SARS-CoV-2 nsp7-11 (blue) and low intensity binding of nsp16 to nsp7-11. Intensity of nsp16 to nsp7-11 is so low that it is not visible in the depicted spectrum. The second spectrum shows a mixture of nsp7-11, nsp16-His6 and the main protease (Mpro). Mpro had fully processed nsp7-11 and thereby liberated nsp10 (blue), which is a cofactor of nsp16 (pink). The binding interaction of nsp16 + 10 (orange), mature nsps nsp72 (olive), nsp8 (green), nsp9 (dark blue) and nsp10 (blue) are shown. B Top mass spectrum shows Middle East respiratory syndrome CoV (MERS-CoV) nsp7-11 (blue) mixed with SARS-CoV-2 nsp16-His6. A low-abundant nsp7-11+nsp16-His6 complex (orange) could be detected. The bottom mass spectrum shows SARS-CoV-2 nsp16 (pink) mixed with fully processed MERS-CoV nsp7-11 by Mpro, resulting in released nsp72 (olive), nsp8 (green), nsp9 (dark blue) and nsp10-11 (blue). Nsp16 + nsp10-11 complex (orange) and nsp7 + 8 (yellow) are detected. C Surface rendered crystal structure (pdb 6W4H) of nsp16 (pink) and nsp10 (blue) illustrates the spatial orientation of C- and N-termini of nsp10 and nsp16 pointing away from each other. Binding experiments for both SARS-CoV-2 and MERS-CoV nsp7-11 were repeated twice. Source data are provided as a Source Data file.
