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Pathway Description
Methionine biosynthesis; Methionine metabolism: metB, metL
Escherichia coli K-12
Category:
Metabolite Pathway
Sub-Category:
Signaling
Created: 2025-03-13
Last Updated: 2025-05-08
The regulation of the operon metBL. The operon is repressed by metJ (Met repressor) when its bound with SAM (S-adenosylmethionine). SAM is required for metJ to bind to the promoter. Therefore, the absence of SAM activates the operon because metJ can no longer bind to the promoter. SAM is a product of the methionine pathway. The operon has two products: metB (Cystathionine gamma-synthase), metL (Bifunctional aspartokinase/homoserine dehydrogenase 2). Both of these products are enzymes used in the methionine biosynthesis. MetB catalyzes the reaction O-succinyl-L-homoserine to L,L-cystathionine. MetL catalyzes two different reactions in the methionine pathway. They include the first step (L-aspartate to 4-phospho-L-aspartate) and the third step (L-aspartate 4-semialdehyde to L-homoserine) in the creation of L-homoserine from L-aspartate.
References
Methionine biosynthesis; Methionine metabolism: metB, metL References
Augustus AM, Spicer LD: The MetJ regulon in gammaproteobacteria determined by comparative genomics methods. BMC Genomics. 2011 Nov 14;12:558. doi: 10.1186/1471-2164-12-558.
Pubmed: 22082356
Rodionov DA, Vitreschak AG, Mironov AA, Gelfand MS: Comparative genomics of the methionine metabolism in Gram-positive bacteria: a variety of regulatory systems. Nucleic Acids Res. 2004 Jun 23;32(11):3340-53. doi: 10.1093/nar/gkh659. Print 2004.
Pubmed: 15215334
Shoeman R, Coleman T, Redfield B, Greene RC, Smith AA, Saint-Girons I, Brot N, Weissbach H: Regulation of methionine synthesis in Escherichia coli: effect of metJ gene product and S-adenosylmethionine on the in vitro expression of the metB, metL and metJ genes. Biochem Biophys Res Commun. 1985 Dec 17;133(2):731-9. doi: 10.1016/0006-291x(85)90965-9.
Pubmed: 3910040
Shoeman R, Coleman T, Redfield B, Greene RC, Smith AA, Saint-Girons I, Brot N, Weissbach H: Regulation of methionine synthesis in Escherichia coli: effect of metJ gene product and S-adenosylmethionine on the in vitro expression of the metB, metL and metJ genes. Biochem Biophys Res Commun. 1985 Dec 17;133(2):731-9. doi: 10.1016/0006-291x(85)90965-9.
Pubmed: 3910040
Duchange N, Zakin MM, Ferrara P, Saint-Girons I, Park I, Tran SV, Py MC, Cohen GN: Structure of the metJBLF cluster in Escherichia coli K12. Sequence of the metB structural gene and of the 5'- and 3'-flanking regions of the metBL operon. J Biol Chem. 1983 Dec 25;258(24):14868-71.
Pubmed: 6361020
Saint-Girons I, Duchange N, Cohen GN, Zakin MM: Structure and autoregulation of the metJ regulatory gene in Escherichia coli. J Biol Chem. 1984 Nov 25;259(22):14282-5.
Pubmed: 6094549
Collier CD, Johnson JR: The Escherichia coli K-12 metJ193 allele contains a point mutation which alters the hydrophobic pocket responsible for in vitro binding of S-adenosylmethionine: effects on cell growth and induction of met regulon expression. J Bacteriol. 1990 Jul;172(7):3918-24. doi: 10.1128/jb.172.7.3918-3924.1990.
Pubmed: 2141834
Plunkett G 3rd, Burland V, Daniels DL, Blattner FR: Analysis of the Escherichia coli genome. III. DNA sequence of the region from 87.2 to 89.2 minutes. Nucleic Acids Res. 1993 Jul 25;21(15):3391-8. doi: 10.1093/nar/21.15.3391.
Pubmed: 8346018
Cossart P, Gicquel-Sanzey B: Cloning and sequence of the crp gene of Escherichia coli K 12. Nucleic Acids Res. 1982 Feb 25;10(4):1363-78. doi: 10.1093/nar/10.4.1363.
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Aiba H, Fujimoto S, Ozaki N: Molecular cloning and nucleotide sequencing of the gene for E. coli cAMP receptor protein. Nucleic Acids Res. 1982 Feb 25;10(4):1345-61. doi: 10.1093/nar/10.4.1345.
Pubmed: 6280140
Blattner FR, Plunkett G 3rd, Bloch CA, Perna NT, Burland V, Riley M, Collado-Vides J, Glasner JD, Rode CK, Mayhew GF, Gregor J, Davis NW, Kirkpatrick HA, Goeden MA, Rose DJ, Mau B, Shao Y: The complete genome sequence of Escherichia coli K-12. Science. 1997 Sep 5;277(5331):1453-62. doi: 10.1126/science.277.5331.1453.
Pubmed: 9278503
Markham GD, DeParasis J, Gatmaitan J: The sequence of metK, the structural gene for S-adenosylmethionine synthetase in Escherichia coli. J Biol Chem. 1984 Dec 10;259(23):14505-7.
Pubmed: 6094561
Satishchandran C, Taylor JC, Markham GD: Isozymes of S-adenosylmethionine synthetase are encoded by tandemly duplicated genes in Escherichia coli. Mol Microbiol. 1993 Aug;9(4):835-46. doi: 10.1111/j.1365-2958.1993.tb01742.x.
Pubmed: 8231813
Hayashi K, Morooka N, Yamamoto Y, Fujita K, Isono K, Choi S, Ohtsubo E, Baba T, Wanner BL, Mori H, Horiuchi T: Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110. Mol Syst Biol. 2006;2:2006.0007. doi: 10.1038/msb4100049. Epub 2006 Feb 21.
Pubmed: 16738553
Allikmets R, Gerrard B, Court D, Dean M: Cloning and organization of the abc and mdl genes of Escherichia coli: relationship to eukaryotic multidrug resistance. Gene. 1993 Dec 22;136(1-2):231-6. doi: 10.1016/0378-1119(93)90470-n.
Pubmed: 7904973
Gal J, Szvetnik A, Schnell R, Kalman M: The metD D-methionine transporter locus of Escherichia coli is an ABC transporter gene cluster. J Bacteriol. 2002 Sep;184(17):4930-2. doi: 10.1128/jb.184.17.4930-4932.2002.
Pubmed: 12169620
Gervais FG, Drapeau GR: Identification, cloning, and characterization of rcsF, a new regulator gene for exopolysaccharide synthesis that suppresses the division mutation ftsZ84 in Escherichia coli K-12. J Bacteriol. 1992 Dec;174(24):8016-22. doi: 10.1128/jb.174.24.8016-8022.1992.
Pubmed: 1459951
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