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Biochemistry. 2017 Sep 19;56(37):4972-4984. doi: 10.1021/acs.biochem.7b00573. Epub 2017 Sep 6.

Nuclear Magnetic Resonance Study of RNA Structures at the 3'-End of the Hepatitis C Virus Genome.

Author information

1
Department of Biochemistry, University of Missouri , Columbia, Missouri 65211, United States.
2
Department of Physics, Department of Biochemistry, and Informatics Institute, University of Missouri , Columbia, Missouri 65211, United States.

Abstract

The 3'-end of the genomic RNA of the hepatitis C virus (HCV) embeds conserved elements that regulate viral RNA synthesis and protein translation by mechanisms that have yet to be elucidated. Previous studies with oligo-RNA fragments have led to multiple, mutually exclusive secondary structure predictions, indicating that HCV RNA structure may be context-dependent. Here we employed a nuclear magnetic resonance (NMR) approach that involves long-range adenosine interaction detection, coupled with site-specific 2H labeling, to probe the structure of the intact 3'-end of the HCV genome (385 nucleotides). Our data reveal that the 3'-end exists as an equilibrium mixture of two conformations: an open conformation in which the 98 nucleotides of the 3'-tail (3'X) form a two-stem-loop structure with the kissing-loop residues sequestered and a closed conformation in which the 3'X rearranges its structure and forms a long-range kissing-loop interaction with an upstream cis-acting element 5BSL3.2. The long-range kissing species is favored under high-Mg2+ conditions, and the intervening sequences do not affect the equilibrium as their secondary structures remain unchanged. The open and closed conformations are consistent with the reported function regulation of viral RNA synthesis and protein translation, respectively. Our NMR detection of these RNA conformations and the structural equilibrium in the 3'-end of the HCV genome support its roles in coordinating various steps of HCV replication.

PMID:
28829576
PMCID:
PMC5643200
DOI:
10.1021/acs.biochem.7b00573
[Indexed for MEDLINE]
Free PMC Article

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