Real time monitoring of the interaction of T7 RNA polymerase with azobenzene-tethered T7 promoter by biosensor.

Abstract

We have already reported that transcription reaction by phage T7 or SP6 RNA polymerase (RNAP) can be reversibly photo-regulated with azobenzene-tethered promoter. Transcription reaction proceeded faster by UV irradiation than visible light irradiation. In the present study, binding of T7 RNAP to its azobenzene-tethered promoter was directly monitored by use of affinity biosensor. When azobenzene-tethered T7 promoter was immobilized on the sensor surface, response based on the binding of RNAP increased by UV light irradiation rather than by visible light irradiation. Thus, photo-regulation of transcription reaction by azobenzene-tethered promoter was attributed to the change of binding property of RNAP to the promoter by trans-cis isomerization of azobenzene.