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Trp-RNA Binding Attenuation Protein (TRAP)

TRAP bound to RNA. PDB code: 1C9S. Antson et al., Nature, 1999.

Many bacteria regulate their production of L-Tryptophan (Trp) by a process called attenuation. When Trp is in abundance it would be inefficient to continue production, hence bacteria have evolved a Trp-concentration dependent regulatory mechanism for its synthesis. This mechanism is coordinated by a circular homo-oligomer protein (of 11 or 12 subunits) named Trp RNA-binding Attenuation protein (TRAP), the structure of which was solved in our group (Antson et al., Nature, 1999). In the presence of Trp, TRAP-Trp complex bind RNA and blocks transcription of the trp operon by forming a terminator stem-loop. In the reverse case, an anti-terminator loop is formed and transcription may proceed.

We have solved the structure of the anti-TRAP protein (AT). If uncharged tRNA-Trp levels become high, synthesis of an anti-TRAP protein is increased which forms a complex with TRAP, inhibiting its termination activity. In this line of work we engineered TRAP to alter its oligomeric state (subunit number) and thermal stability.

trp operon

Regulation of the trp operon by TRAP in bacilli, taken from Antson et al., Nature, 1999.


  • Antson AA, Dodson EJ, Dodson G, Greaves RB, Chen, X-P & Gollnick P: Structure of the trp RNA-binding attenuation protein, TRAP, bound to RNA. (1999) Nature 401, 235-242.
  • Antson AA: Single stranded RNA-binding proteins. (2000) Current Opinion in Structural Biology 10, 87-94.
  • Hopcroft NH, Wendt AL, Gollnick P & Antson AA: Specificity of TRAP-RNA interactions: crystal structures of two complexes with different RNA sequences. Acta Cryst (2002) D58:615-621.
  • Hopcroft NH, Wendt AL, Brzozowski A, Gollnick P, & Antson AA: TRAP-RNA interactions during transcription regulation: the role of spacers and trinucleotide repeats. J. Mol. Biol. (2004) 338:43-53.
  • Shevtsov MB, Chen YL, Gollnick P & Antson AA: Anti-TRAP protein from Bacillus subtilis: crystallization and internal symmetry. Acta Cryst (2004) D60: 1311-1314.
  • Gollnick P & Antson A: Going for RNA repeats. Nature Structural & Molecular Biology (2005) 12: 289 – 290.
  • Gollnick P, Babitzke P, Antson A, Yanofsky C: Complexity in regulation of tryptophan biosynthesis in Bacillus subtilis. Ann. Rev. Genet. (2005) 39: 47-68.
  • Shevtsov MB, Chen Y, Gollnick P and Antson AA: Crystal structure of Bacillus subtilis anti-TRAP protein, an antagonist of TRAP/RNA interaction. Proc. Natl. Acad. Sci. U. S. A., 2005, 102: 17600-17605.
  • Shevtsov MB, Chen Y, Isupov MN, Leech A, Gollnick P, Antson AA. Bacillus licheniformis Anti-TRAP can assemble into two types of dodecameric particles with the same symmetry but inverted orientation of trimers. J Struct Biol., 2010, 170:127-133.
  • Chen C-S, Smits C, Dodson GG, Shevtsov MB, Merlino N, Gollnick P and Antson AA: How to change the oligomeric state of a circular protein assembly: switch from 11-subunit to 12-subunit TRAP suggests a general mechanism. PLoS One 2011, 6: 1-11.
  • Bayfield OW, Chen C-S, Patterson AR, Luan W, Smits C, Gollnick P, Antson AA: Trp RNA-binding attenuation protein: modifying symmetry and stability of a circular oligomer. PLoS ONE, 2012, e44309. doi:10.1371/journal.pone.0044309.