The Spring α-Helix Coordinates Multiple Modes of HCV (Hepatitis C Virus) NS3 Helicase Action.

ABSTRACT: Genomic DNA replication requires helicases to processively unwind duplexes. Although helicases encoded by positive-strand RNA viruses are necessary for RNA genome replication, their functions are not well understood. We determined structures of the hepatitis C virus helicase (NS3h) in complex with the transition state ATP mimic ADP·AlF4 (-) and compared them with the previous nucleic acid-associated ternary complexes. The results suggested that nucleic acid binding promotes a structural change of the spring helix at the transition state, optimizing the interaction network centered on the nucleophilic water. Analysis of ATP hydrolysis with and without conformational restraints on the spring helix further supported the importance of its action for both nucleic acid-stimulated and basal catal

SUBMITTER: Gu M 

PROVIDER: S-EPMC4938173 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature