Location of Repository

Structure and dynamics of the deoxyguanosine-sensing riboswitch studied by NMR-spectroscopy

By Anna Wacker, Janina Buck, Daniel Mathieu, Christian Richter, Jens Wöhnert and Harald (Prof. Dr.) Schwalbe

Abstract

The mfl-riboswitch regulates expression of ribonucleotide reductase subunit in Mesoplasma florum by binding to 2´-deoxyguanosine and thereby promoting transcription termination. We characterized the structure of the ligand-bound aptamer domain by NMR spectroscopy and compared the mfl-aptamer to the aptamer domain of the closely related purine-sensing riboswitches. We show that the mfl-aptamer accommodates the extra 2´-deoxyribose unit of the ligand by forming a more relaxed binding pocket than these found in the purine-sensing riboswitches. Tertiary structures of the xpt-aptamer bound to guanine and of the mfl-aptamer bound to 2´-deoxyguanosine exhibit very similar features, although the sequence of the mfl-aptamer contains several alterations compared to the purine-aptamer consensus sequence. These alterations include the truncation of a hairpin loop which is crucial for complex formation in all purine-sensing riboswitches characterized to date. We further defined structural features and ligand binding requirements of the free mfl-aptamer and found that the presence of Mg2+ is not essential for complex formation, but facilitates ligand binding by promoting pre-organization of key structural motifs in the free aptamer

Topics: ddc:570
Year: 2011
OAI identifier: oai:publikationen.ub.uni-frankfurt.de:22411

Suggested articles

Preview


To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.