Visualizing ATP-dependent RNA Translocation by the NS3 Helicase from HCV

By T. Appleby, R. Anderson, O. Fedorova, Anna Marie Pyle, Ruth Wang, Xiaohong Liu, K. Brendza, J. Somoza. 2010

116 citations recorded by the source corpus.

The structural mechanism by which non-structural protein 3 (NS3) from the hepatitis C virus (HCV) translocates along RNA is currently unknown. HCV NS3 is an ATP-dependent motor protein essential for viral replication and a member of the superfamily 2 (SF2) helicases. Crystallographic analysis using a labeled RNA oligonucleotide allowed us to unambiguously track the positional changes of RNA bound to full-length HCV NS3 during two discrete steps of the ATP hydrolytic cycle. The crystal structures of HCV NS3, NS3 bound to bromine-labeled RNA, and a tertiary complex of NS3 bound to labeled RNA and a non-hydrolyzable ATP analog provide a direct view of how large domain movements resulting from ATP binding and hydrolysis allow the enzyme to translocate along the phosphodiester backbone. While directional translocation of HCV NS3 by a single base pair per ATP hydrolyzed is observed, the 3’-end of the RNA does not shift register with respect to a conserved tryptophan residue, supporting a “spring-loading” mechanism that leads to larger steps by the enzyme as it moves along a nucleic acid substrate.

Subfields: Hepatology, Molecular Biology

Citations in the corpus

• The RIG-I receptor adopts two different conformations for distinguishing host from viral RNA ligands (2022, neutral): “It is important to note that well-folded SF2 proteins sample two closely related conformations (open and closed), which differ in the distance between Hel1 and Hel2 (Appleby et al., 2011; Hamann et al., 2019).”
• Structural insights into RNA recognition by RIG-I (2011, unknown): “S4) and plays key roles in function of the protein (Bono et al., 2006; Del Campo and Lambowitz, 2009; Appleby et al., 2010; Gu and Rice, 2010; Luo et al., 2008; Myong et al., 2007).”