TY  - JOUR
A1  - Doetsch, Martina
A1  - Stampfl, Sabine
A1  - Fürtig, Boris
A1  - Beich-Frandsen, Mads
A1  - Saxena, Krishna
A1  - Lybecker, Meghan
A1  - Schroeder, Renée
T1  - Study of E. coli Hfq's RNA annealing acceleration and duplex destabilization activities using substrates with different GC-contents
T2  - Nucleic acids research
N2  - Folding of RNA molecules into their functional three-dimensional structures is often supported by RNA chaperones, some of which can catalyse the two elementary reactions helix disruption and helix formation. Hfq is one such RNA chaperone, but its strand displacement activity is controversial. Whereas some groups found Hfq to destabilize secondary structures, others did not observe such an activity with their RNA substrates. We studied Hfq’s activities using a set of short RNAs of different thermodynamic stabilities (GC-contents from 4.8% to 61.9%), but constant length. We show that Hfq’s strand displacement as well as its annealing activity are strongly dependent on the substrate’s GC-content. However, this is due to Hfq’s preferred binding of AU-rich sequences and not to the substrate’s thermodynamic stability. Importantly, Hfq catalyses both annealing and strand displacement with comparable rates for different substrates, hinting at RNA strand diffusion and annealing nucleation being rate-limiting for both reactions. Hfq’s strand displacement activity is a result of the thermodynamic destabilization of the RNA through preferred single-strand binding whereas annealing acceleration is independent from Hfq’s thermodynamic influence. Therefore, the two apparently disparate activities annealing acceleration and duplex destabilization are not in energetic conflict with each other.
Y1  - 2012
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/25761
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-257616
UR  - http://www.ncbi.nlm.nih.gov/pmc/articles/pmid/23104381/
SN  - 1362-4962
SN  - 0305-1048
N1  - (c) The Author 2012. Published by Oxford University Press. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc/3.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com.
VL  - 41
IS  - 1
SP  - 487
EP  - 497
PB  - Oxford Univ. Press
CY  - Oxford
ER  -