Crystal structure of Bacillus subtilis anti-TRAP protein, an antagonist of TRAP/RNA interaction

doi:10.1073/pnas.0508728102

Crystal structure of Bacillus subtilis anti-TRAP protein, an antagonist of TRAP/RNA interaction

^*York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5YW, United Kingdom; and ^†Department of Biological Sciences, State University of New York, Buffalo, NY 14260

Communicated by Charles Yanofsky, Stanford University, Stanford, CA, October 7, 2005 (received for review July 12, 2005)

Abstract

In Bacillus subtilis the anti-TRAP protein (AT) is produced in response to the accumulation of uncharged tRNA^Trp. AT regulates expression of genes involved in tryptophan biosynthesis and transport by binding to the tryptophan-activated trp RNA-binding attenuation protein (TRAP) and preventing its interaction with several mRNAs. Here, we report the x-ray structure of AT at 2.8 Å resolution, showing that the protein subunits assemble into tight trimers. Four such trimers are further associated into a 12-subunit particle in which individual trimers are related by twofold and threefold symmetry axes. Twelve DnaJ-like, cysteine-rich zinc-binding domains form spikes on the surface of the dodecamer. Available data suggest several possible ways for AT to interact with the 11-subunit TRAP. Interaction between the two symmetry-mismatching molecules could be assisted by the flexible nature of AT zinc-binding domains.

Footnotes

↵ ‡ To whom correspondence should be addressed. E-mail: fred{at}ysbl.york.ac.uk.
Author contributions: M.B.S. and Y.C. performed research; M.B.S., Y.C., P.G., and A.A.A. analyzed data; P.G. and A.A.A. designed research; and M.B.S., P.G., and A.A.A. wrote the paper.
Conflict of interest statement: No conflicts declared.
Abbreviations: TRAP, trp RNA-binding attenuation protein; AT, anti-TRAP protein.
Data deposition: The atomic coordinates and structure factor amplitudes have been deposited in the Protein Data Bank, www.pdb.org (PDB ID code 2bx9).