3KVU

Structural basis of the activity and substrate specificity of the fluoroacetyl-CoA FlK - T42S mutant in complex with Acetyl-CoA

Summary for 3KVU

• Entry DOI: 10.2210/pdb3kvu/pdb
• Related: 3KUV 3KUW 3KV7 3KV8 3KVI 3KVZ 3KW1 3KX7 3KX8
• Descriptor: Fluoroacetyl-CoA thioesterase FlK, ACETYL COENZYME *A (3 entities in total)
• Functional Keywords: fluoroacetyl-coa thioesterase flk, thioesterase, hot-dog folding, hydrolase
• Biological source: Streptomyces cattleya
• Total number of polymer chains: 4
• Total formula weight: 63490.35

Authors

Dias, M.V.B.,Huang, F.,Chirgadze, D.Y.,Tosin, M.,Spiteller, D.,Valentine, E.F.,Leadlay, P.F.,Spencer, J.B.,Blundell, T.L. (deposition date: 2009-11-30, release date: 2010-04-28, Last modification date: 2023-09-06)

Primary citation

Dias, M.V.,Huang, F.,Chirgadze, D.Y.,Tosin, M.,Spiteller, D.,Dry, E.F.,Leadlay, P.F.,Spencer, J.B.,Blundell, T.L.
Structural basis for the activity and substrate specificity of fluoroacetyl-CoA thioesterase FlK.
J.Biol.Chem., 285:22495-22504, 2010

PubMed Abstract: The thioesterase FlK from the fluoroacetate-producing Streptomyces cattleya catalyzes the hydrolysis of fluoroacetyl-coenzyme A. This provides an effective self-defense mechanism, preventing any fluoroacetyl-coenzyme A formed from being further metabolized to 4-hydroxy-trans-aconitate, a lethal inhibitor of the tricarboxylic acid cycle. Remarkably, FlK does not accept acetyl-coenzyme A as a substrate. Crystal structure analysis shows that FlK forms a dimer, in which each subunit adopts a hot dog fold as observed for type II thioesterases. Unlike other type II thioesterases, which invariably utilize either an aspartate or a glutamate as catalytic base, we show by site-directed mutagenesis and crystallography that FlK employs a catalytic triad composed of Thr(42), His(76), and a water molecule, analogous to the Ser/Cys-His-acid triad of type I thioesterases. Structural comparison of FlK complexed with various substrate analogues suggests that the interaction between the fluorine of the substrate and the side chain of Arg(120) located opposite to the catalytic triad is essential for correct coordination of the substrate at the active site and therefore accounts for the substrate specificity.

PubMed: 20430898
DOI: 10.1074/jbc.M110.107177

Experimental method

X-RAY DIFFRACTION (2 Å)