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The nature of the TRAP-Anti-TRAP complex.

ABSTRACT: Tryptophan biosynthesis is subject to exquisite control in species of Bacillus and has become one of the best-studied model systems in gene regulation. The protein TRAP (trp RNA-binding attenuation protein) predominantly forms a ring-shaped 11-mer, which binds cognate RNA in the presence of tryptophan to suppress expression of the trp operon. TRAP is itself regulated by the protein Anti-TRAP, which binds to TRAP and prevents RNA binding. To date, the nature of this interaction has proved elusive. Here, we describe mass spectrometry and analytical centrifugation studies of the complex, and 2 crystal structures of the TRAP-Anti-TRAP complex. These crystal structures, both refined to 3.2-A resolution, show that Anti-TRAP binds to TRAP as a trimer, sterically blocking RNA binding. Mass spectrometry shows that 11-mer TRAP may bind up to 5 AT trimers, and an artificial 12-mer TRAP may bind 6. Both forms of TRAP make the same interactions with Anti-TRAP. Crystallization of wild-type TRAP with Anti-TRAP selectively pulls the 12-mer TRAP form out of solution, so the crystal structure of wild-type TRAP-Anti-TRAP complex reflects a minor species from a mixed population.

SUBMITTER: Watanabe M

PROVIDER: S-EPMC2650128 | biostudies-literature | 2009 Feb

REPOSITORIES: biostudies-literature

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The nature of the TRAP-Anti-TRAP complex.

Watanabe Masahiro M Heddle Jonathan G JG Kikuchi Kenichi K Unzai Satoru S Akashi Satoko S Park Sam-Yong SY Tame Jeremy R H JR

Proceedings of the National Academy of Sciences of the United States of America 20090122 7

Tryptophan biosynthesis is subject to exquisite control in species of Bacillus and has become one of the best-studied model systems in gene regulation. The protein TRAP (trp RNA-binding attenuation protein) predominantly forms a ring-shaped 11-mer, which binds cognate RNA in the presence of tryptophan to suppress expression of the trp operon. TRAP is itself regulated by the protein Anti-TRAP, which binds to TRAP and prevents RNA binding. To date, the nature of this interaction has proved elusive ...[more]

PMID: 19164760

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The nature of the TRAP-Anti-TRAP complex.

Publications

The nature of the TRAP-Anti-TRAP complex.

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