Poster abstracts

Poster number 45 submitted by Moulisubhro Datta

Exploring the roles of protein cofactors in the conformational dynamics and regulation of RNase P

Milo Datta (MCDB), Ila Marathe (Post doctoral candidate, OSU)

Abstract:
tRNAs are adapter molecules playing crucial role in cellular translation. For these molecules to be functional, multiple enzymes process the premature tRNAs into the final mature form. RNase P is one such processor, catalyzing Mg2+ dependent 5′ maturation of precursor tRNAs (pre-tRNAs). The ribonucleoprotein (RNP) form of the enzyme utilizes a catalytic RNA aided by proteins. Across the spectrum of life, different numbers of RNase P Proteins (RPPs) associate with the RNase P RNA (RPR) to form the functional holoenzyme. Archaea possess up to 5 RPPs which share high homology with their eukaryotic counterparts who possess up to 10 RPPs. This makes the archaeal system a good model to biochemically explore the roles of the proteins in the RNP assembly and function. In archaea, the proteins are: RPP21, RPP29, POP5, RPP30 and L7Ae. RPP21•RPP29 and POP5•RPP30 form binary subcomplexes that bind the RPR, helping in substrate binding and catalysis respectively. Recent structural studies showed that RPR of Pyrococcus furiosus (Pfu), an archaeon, undergoes Mg2+ induced structural remodeling, through different paths, in the presence or absence of the RPPs. Effect of individual RPP components on the RPR structural reorganization is unknown. Furthermore, characterization of the RPPs in metal ion affinity and RPR binding is still required. The proposed study in the archaeal RNase P system seeks to unravel the contributions of RPPs in RPR conformational dynamics and regulation. Single molecule experiments will give insights into the role of RPPs in RPR binding and folding and cleavage assays with individual suites of RPP binary complexes will parse their roles in metal ion binding. The studies will help gain deeper insights into the archaeal RNase P enzyme and a better understanding of the system in eukaryotes.

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Keywords: tRNA processing, RNase P, conformational dynamics