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Electrochemically Induced Modulation of the Catalytic Activity of a Reversible Redoxsensitive Riboswitch
Author(s) -
Strohbach Denise,
Turcu Florin,
Schuhmann Wolfgang,
Müller Sabine
Publication year - 2008
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200704173
Subject(s) - ribozyme , flavin mononucleotide , chemistry , allosteric regulation , riboswitch , rna , flavin group , catalysis , biophysics , stereochemistry , photochemistry , biochemistry , enzyme , non coding rna , biology , gene
Over the past decade, RNA conformation has been shown to respond to external stimuli. Thus, dependent on the presence of a high affinity ligand, specifically designed ribozymes can be regulated in a classical allosteric way. In this scenario, a binding event in one part of the RNA structure induces conformational changes in a separated part, which constitutes the catalytic centre. As a result activity is switched on (positive regulation) or off (negative regulation). We have developed a hairpin aptazyme responding to flavine mononucleotide (FMN). Ribozyme activity is dependent on binding of FMN and thus is switched on in the presence of FMN in its oxidized form. Under reducing conditions, however, FMN changes its molecular geometry, which is associated with loss of binding and consequently down‐regulation of ribozyme activity. While in previous experiments sodium dithionite was used for reduction of FMN, we now present an assay for electrochemically induced activity switching. We have developed an electrochemical microcell that allows for iterative cycles of reduction/oxidation of FMN in an oxygen free atmosphere and thus for reversible switching of ribozyme activity. The reaction proceeds in droplets of 3 to 10 μL at micro‐ to nanomolar concentrations of the reaction components.