Structural basis for the selectivity of the external thioesterase of the surfactin synthetase

Nature. 2008 Aug 14;454(7206):907-11. doi: 10.1038/nature07161.


Non-ribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) found in bacteria, fungi and plants use two different types of thioesterases for the production of highly active biological compounds. Type I thioesterases (TEI) catalyse the release step from the assembly line of the final product where it is transported from one reaction centre to the next as a thioester linked to a 4'-phosphopantetheine (4'-PP) cofactor that is covalently attached to thiolation (T) domains. The second enzyme involved in the synthesis of these secondary metabolites, the type II thioesterase (TEII), is a crucial repair enzyme for the regeneration of functional 4'-PP cofactors of holo-T domains of NRPS and PKS systems. Mispriming of 4'-PP cofactors by acetyl- and short-chain acyl-residues interrupts the biosynthetic system. This repair reaction is very important, because roughly 80% of CoA, the precursor of the 4'-PP cofactor, is acetylated in bacteria. Here we report the three-dimensional structure of a type II thioesterase from Bacillus subtilis free and in complex with a T domain. Comparison with structures of TEI enzymes shows the basis for substrate selectivity and the different modes of interaction of TEII and TEI enzymes with T domains. Furthermore, we show that the TEII enzyme exists in several conformations of which only one is selected on interaction with its native substrate, a modified holo-T domain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis / enzymology*
  • Bacterial Proteins / biosynthesis
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / metabolism*
  • Fatty Acid Synthases / chemistry*
  • Fatty Acid Synthases / metabolism*
  • Models, Molecular
  • Nuclear Magnetic Resonance, Biomolecular
  • Peptide Synthases / biosynthesis
  • Peptide Synthases / chemistry*
  • Peptide Synthases / metabolism*
  • Protein Interaction Domains and Motifs
  • Protein Structure, Tertiary
  • Thiolester Hydrolases / chemistry*
  • Thiolester Hydrolases / metabolism*


  • Bacterial Proteins
  • Fatty Acid Synthases
  • Thiolester Hydrolases
  • thioesterase II
  • Peptide Synthases
  • surfactin synthetase

Associated data

  • PDB/2K2Q
  • PDB/2RON