Structural basis for the selectivity of the external thioesterase of the surfactin synthetase.
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.
Koglin
Alexander
A
Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance and Cluster of Excellence Macromolecular Complexes (CEF), J.W.-Goethe University, 60438 Frankfurt am Main, Germany.
Löhr
Frank
F
Bernhard
Frank
F
Rogov
Vladimir V
VV
Frueh
Dominique P
DP
Strieter
Eric R
ER
Mofid
Mohammad R
MR
Güntert
Peter
P
Wagner
Gerhard
G
Walsh
Christopher T
CT
Marahiel
Mohamed A
MA
Dötsch
Volker
V
D001412:Bacillus subtilis / Q000201:enzymology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism*; D064429:Fatty Acid Synthases / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D010453:Peptide Synthases / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D017434:Protein Structure, Tertiary; D013869:Thiolester Hydrolases / Q000737:chemistry* / Q000378:metabolism*
D001426:Bacterial Proteins; D064429:Fatty Acid Synthases; D013869:Thiolester Hydrolases; C022738:thioesterase II; D010453:Peptide Synthases; C069542:surfactin synthetase