Poster abstracts

Poster number 8 submitted by Rajaneesh Anupam

Binding of Small Molecules to T Box Antiterminator Model

Rajaneesh Anupam (Department of Chemistry and Biochemistry, Ohio University), Jennifer Hines (Department of Chemistry and Biochemistry, Ohio University)

Abstract:
Bacillus subtilis tyrS is an aminoacyl-tRNA synthetase gene that is regulated by the T box transcription antitermination mechanism. Expression of this gene is regulated by the interaction of uncharged tRNA^Tyr with the 5' untranslated region of the nascent mRNA. One feature of this interaction is the base pairing of the tRNA acceptor end with four bases of a highly conserved mRNA structural element termed the antiterminator. This tRNA-antiterminator base pairing prevents the formation of an alternative terminator element and results in antitermination of transcription. The binding of small molecules to the antiterminator model RNAs was investigated to determine ligand structure-activity relationship for binding and to investigate the effect of antiterminator sequence differences on binding specificity. AM1A and AM1A(C11U) were studied using fluorescence resonance energy transfer (FRET). AM1A(C11U) is a reduced function variant of the wild-type model AM1A and has subtle but significant structural differences compared to AM1A. Oxazolidinones and aminoglycosides were the classes of RNA ligands investigated. Several ligands were identified which bond selectively to AM1A. Ligands with high affinity to AM1A were also investigated via enzymatic footprinting and molecular modeling to identify the site of binding.

Keywords: FRET, Footprinting, Oxazolidinones