Structural insights of the conserved "priming loop" of hepatitis B virus pre-genomic RNA.
LeBlanc, R.M., Kasprzak, W.K., Longhini, A.P., Olenginski, L.T., Abulwerdi, F., Ginocchio, S., Shields, B., Nyman, J., Svirydava, M., Del Vecchio, C., Ivanic, J., Schneekloth Jr., J.S., Shapiro, B.A., Dayie, T.K., Le Grice, S.F.J.(2021) J Biomol Struct Dyn : 1-13
- PubMed: 34155954 
- DOI: https://doi.org/10.1080/07391102.2021.1934544
- Primary Citation of Related Structures:  
6VAR - PubMed Abstract: 
Initiation of protein-primed (-) strand DNA synthesis in hepatitis B virus (HBV) requires interaction of the viral polymerase with a cis -acting regulatory signal, designated epsilon (ε), located at the 5'-end of its pre-genomic RNA (pgRNA). Binding of polymerase to ε is also necessary for pgRNA encapsidation. While the mechanistic basis of this interaction remains elusive, mutagenesis studies suggest its internal 6-nt "priming loop" provides an important structural contribution. ε might therefore be considered a promising target for small molecule interventions to complement current nucleoside-analog based anti-HBV therapies. An ideal prerequisite to any RNA-directed small molecule strategy would be a detailed structural description of this important element. Herein, we present a solution NMR structure for HBV ε which, in combination with molecular dynamics and docking simulations, reports on a flexible ligand "pocket", reminiscent of those observed in proteins. We also demonstrate the binding of the selective estrogen receptor modulators (SERMs) Raloxifene, Bazedoxifene, and a de novo derivative to the priming loop.Communicated by Ramaswamy H. Sarma.
Organizational Affiliation: 
Basic Research Laboratory, National Cancer Institute, Frederick, MD, USA.