Conformational dynamics of the tetracycline-binding aptamer

The conformational dynamics induced by ligand binding to the tetracycline-binding aptamer is monitored via stopped-flow fluorescence spectroscopy and time-correlated single photon counting experiments. The fluorescence o
The conformational dynamics induced by ligand binding to the tetracycline-binding aptamer is monitored via stopped-flow fluorescence spectroscopy and time-correlated single photon counting experiments. The fluorescence of the ligand is sensitive to changes within the tertiary structure of the aptamer during and after the binding process. In addition to the wild-type aptamer, the mutants A9G, A13U and A50U are examined, where bases important for regulation are changed to inhibit the aptamer’s function. Our results suggest a very fast two-step-mechanism for the binding of the ligand to the aptamer that can be interpreted as a binding step followed by a reorganization of the aptamer to accommodate the ligand. Binding to the two direct contact points A13 and A50 was found to occur in the first binding step. The exchange of the structurally important base A9 for guanine induces an enormous deceleration of the overall binding process, which is mainly rooted in an enhancement of the back reaction of the first binding step by several orders of magnitude. This indicates a significant loss of tertiary structure of the aptamer in the absence of the base A9, and underlines the importance of pre-organization on the overall binding process of the tetracycline-binding aptamer.
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Metadaten
Author:Ute Förster, Julia E. Weigand, Peter Trojanowski, Beatrix Süß, Josef Wachtveitl
URN:urn:nbn:de:hebis:30:3-250088
DOI:http://dx.doi.org/10.1093/nar/gkr835
ISSN:1362-4962
ISSN:0305-1048
Pubmed Id:http://www.ncbi.nlm.nih.gov/pubmed?term=22053085
Parent Title (English):Nucleic acids research
Publisher:Oxford Univ. Press
Place of publication:Oxford
Document Type:Article
Language:English
Date of Publication (online):2011/11/03
Date of first Publication:2011/11/03
Publishing Institution:Univ.-Bibliothek Frankfurt am Main
Release Date:2012/06/08
Volume:40
Pagenumber:11
First Page:1807
Last Page:1817
Institutes:Biochemie und Chemie
Biowissenschaften
Dewey Decimal Classification:570 Biowissenschaften; Biologie
Sammlungen:Universitätspublikationen
Sondersammelgebiets-Volltexte
Licence (German):License LogoCreative Commons - Namensnennung-Nicht kommerziell 3.0

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