Binding of 2′-Amino-2′-Deoxycytidine-5′-Triphosphate to Norovirus Polymerase Induces Rearrangement of the Active Site

Crystal structures of a genogroup II.4 human norovirus polymerase bound to an RNA primer-template duplex and the substrate analogue 2'-amino-2'-deoxycytidine-5'-triphosphate have been determined to 1.8 angstrom resolution. The alteration of the substrate-binding site that is required to accommodate the 2'-amino group leads to a rearrangement of the polymerase active site and a disruption of the coordination shells of the active-site metal ions. The mode of binding seen for 2'-amino-2'-deoxycytidine-5'-triphosphate suggests a novel molecular mechanism of inhibition that may be exploited for the design of inhibitors targeting viral RNA polymerases. (C) 2009 Elsevier Ltd. All rights reserved.