Characterisation of novel functions of the active centre of RNA polymerase

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Realisation of genetic information requires the copying of information coded in DNA into RNA, transcription. Afterwards this information, in the form of RNA, is either directly used by the cell or decoded into proteins during translation. In all living organisms transcription is performed by multisubunit RNA polymerases, enzymes highly conserved in evolution from bacteria to humans. Though RNA polymerase has been actively investigated for 30 years, most heavily during the last decade, the mechanisms that govern its functions are still not fully understood. Especially interesting and at the same time obscure is the functioning of the active centre of RNA polymerase, one of the most ancient protein active centres on Earth. The mechanisms ensuring accuracy, and processivity of transcription are still unclear. Furthermore, it even appears that not all of the reactions that can be catalysed by the RNA polymerase active centre are known. From an applied perspective, characterisation of the active centre of RNA polymerase is also important for drug discovery, since it is the target for potent antibiotics. Recently we have described several new features of the active centre of RNA polymerase that are important for complete understanding of its molecular function. In this proposal we will characterise the newly discovered RNA ligation reaction and search for its significance in RNA polymerase function. We will also investigate the complex mechanisms responsible for coordination and stabilisation of substrates in the active centre of RNA polymerase, and for the conformational switches in the active centre that precede catalysis in all of the reactions performed by RNA polymerase. Finally, we will search for previously unrecognised mechanisms, and new reactions of RNA polymerase. This will help to build a comprehensive picture of the mechanisms involved in transcription.