{PDOC00403} {PS00441; CHALCONE_SYNTH} {BEGIN} *********************************************** * Chalcone and stilbene synthases active site * *********************************************** Chalcone synthases (CHS) (EC 2.3.1.74) and stilbene synthases (STS) (formerly known as resveratrol synthases) are related plant enzymes [1]. CHS is an important enzyme in flavanoid biosynthesis and STS a key enzyme in stilbene- type phyloalexin biosynthesis. Both enzymes catalyze the addition of three molecules of malonyl-CoA to a starter CoA ester (a typical example is 4-coumaroyl-CoA), producing either a chalcone (with CHS) or stilbene (with STS). These enzymes are proteins of about 390 amino-acid residues. A conserved cysteine residue, located in the central section of these proteins, has been shown [2] to be essential for the catalytic activity of both enzymes and probably represents the binding site for the 4-coumaryl-CoA group. The region around this active site residue is well conserved and can be used as a signature pattern. In addition to the plant enzymes, this family also includes Bacillus subtilis bcsA. -Consensus pattern: R-[LIVMFYS]-x-[LIVM]-x-[QHG]-x-G-C-[FYNA]-[GAPV]-G-[GAC]- [STAVK]-x-[LIVMF]-[RAL] [C is the active site residue] -Sequences known to belong to this class detected by the pattern: ALL. -Other sequence(s) detected in Swiss-Prot: NONE. -Expert(s) to contact by email: Schroeder J.; jschroe@ruf.uni-freiburg.de -Last update: December 2004 / Pattern and text revised. [ 1] Schroeder J., Schroeder G. Z. Naturforsch. 45C:1-8(1990). [ 2] Lanz T., Tropf S., Marner F.-J., Schroeder J., Schroeder G. "The role of cysteines in polyketide synthases. Site-directed mutagenesis of resveratrol and chalcone synthases, two key enzymes in different plant-specific pathways." J. Biol. Chem. 266:9971-9976(1991). PubMed=2033084 -------------------------------------------------------------------------------- PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html -------------------------------------------------------------------------------- {END}