Poster abstracts
Poster number 95 submitted by Kumudie Jayalath
Pseudouridylation enzyme RsuA influence 30S ribosome assembly
Kumudie Jayalath (Chemistry & Biochemistry, Kent State University), Minhchau To (Chemistry & Biochemistry, Kent State University), Sanjaya Abey (Chemistry & Biochemistry, Kent State University)
Abstract:
Ribosome is the Ribonucleoprotein complex that is responsible for protein biosynthesis in all living organisms. Bacterial ribosome biogenesis is a complex process that requires synchronization of various cellular events including ribosomal RNA (rRNA) transcription, ribosome assembly, RNA processing and post-transcriptional modification of rRNA. Ribosomal RNA nucleotide modifications and their respective modification enzymes can modulate rRNA folding and ribosome assembly. The only pseudouridine modification found in E. coli 16S ribosomal RNA is located at position 516 of 16S helix 18 which forms the central pseudoknot of the 30S ribosomal subunit. Our circular dichroism spectroscopic data suggest that the helix 18 model RNA undergoes Mg2+-dependent structural changes only in the presence of the pseudouridine modification at position 516. A FRET-based RsuA binding assay developed in our lab shows thermodynamic anti-cooperativity between ribosomal protein S4 and RsuA that catalyzes pseudouridylation of U516. Furthermore, as observed with a reverse transcriptase based activity assay, RsuA is catalytically cooperative with ribosomal protein S17. Our data suggests that the RsuA enzyme binds preferably to non-pseudoknoted (extended) helix 18 that is also important for its function.
Keywords: Ribosome biogenesis, RNA modification enzyme , Pseudouridine