{PDOC00677} {PS00868; CYS_MET_METAB_PP} {BEGIN} ****************************************************************** * Cys/Met metabolism enzymes pyridoxal-phosphate attachment site * ****************************************************************** A number of pyridoxal-dependent enzymes involved in the metabolism of cysteine, homocysteine and methionine have been shown [1,2] to be evolutionary related. These are: - Cystathionine gamma-lyase (EC 4.4.1.1) (gamma-cystathionase), which catalyzes the transformation of cystathionine into cysteine, oxobutanoate and ammonia. This is the final reaction in the transulfuration pathway that leads from methionine to cysteine in eukaryotes. - Cystathionine gamma-synthase (EC 2.5.1.48), which catalyzes the conversion of cysteine and succinyl-homoserine into cystathionine and succinate: the first step in the biosynthesis of methionine from cysteine in bacteria (gene metB). - Cystathionine beta-lyase (EC 4.4.1.8) (beta-cystathionase), which catalyzes the conversion of cystathionine into homocysteine, pyruvate and ammonia: the second step in the biosynthesis of methionine from cysteine in bacteria (gene metC). - Methionine gamma-lyase (EC 4.4.1.11) (L-methioninase) which catalyzes the transformation of methionine into methanethiol, oxobutanoate and ammonia. - OAH/OAS sulfhydrylase, which catalyzes the conversion of acetylhomoserine into homocysteine and that of acetylserine into cysteine (gene MET17 or MET25 in yeast). - O-succinylhomoserine sulfhydrylase (EC 4.2.99.-). - Yeast hypothetical protein YGL184c. - Yeast hypothetical protein YHR112c. These enzymes are proteins of about 400 amino-acid residues. The pyridoxal-P group is attached to a lysine residue located in the central section of these enzymes; the sequence around this residue is highly conserved and can be used as a signature pattern to detect this class of enzymes. -Consensus pattern: [DQ]-[LIVMFY]-x(3)-[STAGCN]-[STAGCIL]-T-K-[FYWQI]-[LIVMF]- x-G-[HQD]-[SGNH] [K is the pyridoxal-P attachment site] -Sequences known to belong to this class detected by the pattern: ALL. -Other sequence(s) detected in Swiss-Prot: NONE. -Last update: December 2004 / Pattern and text revised. [ 1] Ono B.I., Tanaka K., Naito K., Heike C., Shinoda S., Yamamoto S., Ohmori S., Oshima T., Toh-E A. "Cloning and characterization of the CYS3 (CYI1) gene of Saccharomyces cerevisiae." J. Bacteriol. 174:3339-3347(1992). PubMed=1577698; [ 2] Barton A.B., Kaback D.B., Clark M.W., Keng T., Ouellette B.F.F., Storms R.K., Zeng B., Zhong W.W., Fortin N., Delaney S., Bussey H. "Physical localization of yeast CYS3, a gene whose product resembles the rat gamma-cystathionase and Escherichia coli cystathionine gamma-synthase enzymes." Yeast 9:363-369(1993). PubMed=8511966; -------------------------------------------------------------------------------- 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}