The non-structural protein Nsp10 of mouse hepatitis virus binds zinc ions and nucleic acids

The non-structural protein Nsp10 of coronaviruses is a small cleavage product of the viral replicase polyprotein that has been implicated in RNA synthesis. Nsp10 of mouse hepatitis virus (MHV) displays an apparent molecular mass of 13-16 kDa in reducing SDS-PAGE and analytical gel filtration, while dynamic light scattering suggests the existence of oligomeric forms. Atomic absorption spectroscopy reveals two metal ions per Nsp10 monomer, with a preference for Zn2+ over Fe2+/3+ and Co2+. These are probably bound by two Zn-finger-like motifs. Moreover, MHV Nsp10 interacts with tRNA, single-stranded RNA, double-stranded DNA and, to a lesser extent, single-stranded DNA as shown by gel-shift experiments. The K-d for tRNA is 2.1 +/- 0.2 mu M. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.