Poster abstracts

Poster number 21 submitted by Karen Jack

In vitro Analysis of Mg²⁺ Interactions within the T Box Transcription Regulatory Mechanism

Karen D. Jack (Chemistry and Biochemistry, Ohio University), Jennifer V. Hines (Chemistry and Biochemistry, Ohio University)

Abstract:
Many Gram-positive bacterial genes use the T box transcription antitermination mechanism to control transcription via a RNA-RNA interaction between uncharged, cognate tRNA and the mRNA leader region of the gene transcript. The tRNA is recognized by at least two regions of the leader. The specifier sequence, or codon, binds the anticodon of the tRNA, and the antiterminator binds the acceptor end of the uncharged tRNA. Previous studies of this system have shown that the secondary structure of the mRNA leader region, tertiary structure of the antiterminator, and the complex with the uncharged tRNA play a fundamental role in antitermination in vivo and tRNA binding in vitro. Interest in the stability and versatility of RNA structure formation has identified Mg²⁺ as a critical factor in the folding, structural integrity, and biological function of RNA. The hypothesis of this research is that Mg²⁺ is involved in direct interactions with the T box antiterminator as well as in the stabilization of the mRNA/ tRNA binding event. These studies are important in order to understand the structure-function relationship of this novel regulatory system. Spectroscopic (UV, CD, NMR) as well as terbium (III) footprinting data representing the effects of Mg²⁺ and its relevant probes [Co(NH₃)₆³⁺ and Mn²⁺ on the antiterminator and its complex with model tRNA will be presented.

Keywords: mRNA-tRNA interaction, metal ions, NMR