Fig. 1.

Overall structure of the nsp14–nsp10 complex. (A) Domain organization of nsp14 and nsp10. Domain boundaries are marked with residue numbers. (B) Cartoon representation of the structure of the nsp14–nsp10 heterodimer. Nsp10, the ExoN domain, the N7-MTase domain, and the loop at the N terminus of N7-MTase are marked red, green, marine, and pink, respectively. Invisible residues from 454 to 464 of nsp14 are shown by a dashed line. Magnesium, zinc ions, and the N7-MTase substrates SAH and GpppA are shown as spheres and are colored magenta, gray, yellow, and light pink, respectively. Three zinc fingers (ZF) of nsp14 are highlighted with residues shown as sticks.