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Title: Structural model of an mRNA in complex with the bacterial chaperone Hfq

The Sm-like protein Hfq (host factor Q-beta phage) facilitates regulation by bacterial small noncoding RNAs (sRNAs) in response to stress and other environmental signals. In this paper, we present a low-resolution model of Escherichia coli Hfq bound to the rpoS mRNA, a bacterial stress response gene that is targeted by three different sRNAs. Selective 2'-hydroxyl acylation and primer extension, small-angle X-ray scattering, and Monte Carlo molecular dynamics simulations show that the distal face and lateral rim of Hfq interact with three sites in the rpoS leader, folding the RNA into a compact tertiary structure. These interactions are needed for sRNA regulation of rpoS translation and position the sRNA target adjacent to an sRNA binding region on the proximal face of Hfq. Finally, our results show how Hfq specifically distorts the structure of the rpoS mRNA to enable sRNA base pairing and translational control.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Johns Hopkins Univ., Baltimore, MD (United States). Cell, Molecular and Developmental Biology and Biophysics Program
  2. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). Center for Neutron Research
  3. National Inst. of Health, Frederick, MD (United States). National Cancer Inst. Center for Cancer Research. Structural Biophysics Lab.
  4. Johns Hopkins Univ., Baltimore, MD (United States). T. C. Jenkins Dept. of Biophysics
Publication Date:
OSTI Identifier:
1168867
Grant/Contract Number:
AC02-06CH11357; R01 GM46686; CHE-1265821; EP/K039121/1
Type:
Accepted Manuscript
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 111; Journal Issue: 48; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Johns Hopkins Univ., Baltimore, MD (United States)
Sponsoring Org:
USDOE; National Inst. of Health (NIH) (United States); National Science Foundation (NSF); Engineering and Physical Sciences Research Council (EPSRC)
Contributing Orgs:
National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); National Inst. of Health, Frederick, MD (United States)
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES; small noncoding RNA; RNA–protein interactions; SAXS; Lsm protein; bacterial posttranscriptional control