A Different Trip for Making Trp

Science's STKE  18 Sep 2001:
Vol. 2001, Issue 100, pp. tw337
DOI: 10.1126/stke.2001.100.tw337

Prokaryotes such as Escherichia coli and Bacillus subtilis regulate the production of their own amino acids for protein synthesis. In the synthesis of tryptophan (Trp), both of these bacteria recognize Trp and its uncharged transfer RNA (tRNA) as regulatory signals. Valbuzzi and Yanofsky (see the Perspective by Losick and Sonenshein) show that these signals are not used in B. subtilis along the lines of the classic E. coli model. In B. subtilis, Trp activates the protein TRAP, which in turn binds to the trp leader RNA to promote the formation of a transcription termination structure, thereby limiting Trp production. The signal provided by uncharged tRNATrp promotes the production of the protein AT, which binds directly to Trp-activated TRAP. TRAP is thus prevented from binding to RNA and is inactivated, which leads to antitermination and increases trp operon expression.

A. Valbuzzi, C. Yanofsky, Inhibition of the B. subtilis regulatory protein TRAP by the TRAP-inhibitory protein, AT. Science 293, 2057-2059 (2001). [Abstract] [Full Text]

R. Losick, A. L. Sonenshein, Turning gene regulation on its head. Science 293, 2018-2019 (2001). [Full Text]