Interdisciplinary Graduate Programs Symposium
2010 OSU Molecular Life Sciences
Interdisciplinary Graduate Programs Symposium
|
|
|
|
|
Poster abstracts
Abstract:
In Bacilli, the oligomeric protein TRAP is activated by the binding of tryptophan to bind a nascent trp operon mRNA transcript. This stops further transcription and prevents expression of tryptophan biosynthetic components. The protein Anti-TRAP (AT) binds Trp-TRAP, preventing RNA binding, and allowing transcription to proceed. TRAP and Anti-TRAP represent an excellent model system for studying both protein-nucleic acid and protein-protein interactions. Although significant biochemical data show that AT blocks the TRAP/RNA interface, the mode of the AT/TRAP interaction is poorly understood in terms of the stoichiometry, affinity and structural basis. The puzzle is compounded by the differing oligomeric states of the components: AT exists as both 3-mers and 12-mers while TRAP exists as 11 or 12-mers. To investigate the solution structure of the AT/TRAP complex, small-angle X-ray scattering (SAXS) experiments were performed on various ratios of AT to TRAP. SAXS provides in-solution information about macromolecular folding, aggregation, and structural conformation at 10-50Å resolution. Our results indicate that large supramolecular complexes form at intermediate (2-3 AT3/TRAP11) ratios, whereas condensed structures are favored at higher (5+ AT3/TRAP11) ratios. Together, these findings provide an improved understanding of protein complex formation and versatility.
References:
Watanabe M. (2009) The nature of the TRAP-Anti-TRAP complex. PNAS 106:2176-2181
Shevtsov M. (2005) Crystal structure of Bacillus subtilis anti-TRAP protein, and antagonist of TRAP/RNA interaction. PNAS 102:17600-17605
Snyder D. (2004) Interaction of the trp RNA-binding Attenuation Protein (TRAP) with Anti-TRAP. J. Mol. Biol. 338:669-682
Keywords: SAXS, TRAP, Anti-TRAP
