|Gene:||murI||Accession Numbers: EG11204 (EcoCyc), b3967, ECK3959|
Synonyms: yijA, dga, glr
Physiological concentrations of UDP-N-acetylmuramyl-L-Ala, the second substrate of the subsequent reaction in peptidoglycan biosynthesis, specifically activates the enzyme [Doublet94]. It was suggested that the unique N terminus of MurI is required for activation [Ho95]; however, an N-terminally truncated enzyme is still activated by UDP-N-acetylmuramyl-L-Ala [Doublet96]. Site-directed mutagenesis of the two conserved cysteine residues showed that they are essential for enzymatic activity, suggesting that they are involved in the two-base reaction mechanism [Ho95, Doublet96].
Evidence regarding the quarternary structure of MurI was contradictory: [Yoshimura93] reported a homodimer, while [Doublet94] report that the enzyme is monomeric. A crystal structure of MurI in complex with UDP-N-acetylmuramyl-L-Ala has been solved at 1.9 Å resolution and shows a monomer. The activator binds in a hinge region opposite to the catalytically active site [Lundqvist07].
A D-glutamate-requiring strain first isolated in the E. coli B background carries two independent mutations, one in the glutamate transporter GltS and a second in MurI [Dougherty93, Doublet93]. murI is an essential gene [Doublet93, Baliko93].
Peptide inhibitors of glutamate racemase activity have been identified [Kim00c].
Dga: "D-glutamate auxotrophy"
Glr: "glutamate racemase" [Yoshimura93]
|Map Position: [4,163,451 -> 4,164,308] (89.74 centisomes, 323°)||Length: 858 bp / 285 aa|
Molecular Weight of Polypeptide: 31.002 kD (from nucleotide sequence), 31.0 kD (experimental) [Doublet93 ]
Unification Links: ASAP:ABE-0012989 , CGSC:29401 , DIP:DIP-10283N , EchoBASE:EB1189 , EcoGene:EG11204 , EcoliWiki:b3967 , Mint:MINT-1222611 , ModBase:P22634 , OU-Microarray:b3967 , PortEco:murI , PR:PRO_000023319 , Pride:P22634 , Protein Model Portal:P22634 , RefSeq:NP_418402 , RegulonDB:EG11204 , SMR:P22634 , String:511145.b3967 , UniProt:P22634
Relationship Links: InterPro:IN-FAMILY:IPR001920 , InterPro:IN-FAMILY:IPR004391 , InterPro:IN-FAMILY:IPR015942 , InterPro:IN-FAMILY:IPR018187 , Panther:IN-FAMILY:PTHR21198 , PDB:Structure:2JFN , Pfam:IN-FAMILY:PF01177 , Prosite:IN-FAMILY:PS00923 , Prosite:IN-FAMILY:PS00924
|Biological Process:||GO:0009252 - peptidoglycan biosynthetic process
[UniProtGOA12, UniProtGOA11a, GOA06, GOA01a, Doublet93]
GO:0006807 - nitrogen compound metabolic process [GOA01a]
GO:0008152 - metabolic process [GOA01a]
GO:0008360 - regulation of cell shape [UniProtGOA11a]
GO:0071555 - cell wall organization [UniProtGOA11a]
|Molecular Function:||GO:0008881 - glutamate racemase activity
[GOA06, GOA01, GOA01a, Doublet94]
GO:0016853 - isomerase activity [UniProtGOA11a]
GO:0016855 - racemase and epimerase activity, acting on amino acids and derivatives [GOA01a]
GO:0036361 - racemase activity, acting on amino acids and derivatives [GOA01a]
|MultiFun Terms:||cell structure → murein|
|metabolism → biosynthesis of macromolecules (cellular constituents) → murein (peptidoglycan)|
|Growth Medium||Growth?||T (°C)||O2||pH||Osm/L||Growth Observations|
|LB Lennox||No||37||Aerobic||7||No [Baba06, Comment 1]|
Enzymatic reaction of: glutamate racemase
EC Number: 126.96.36.199
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.
This reaction is reversible. [Doublet94]
The equilibrium constant of the reaction is 1.1 [Doublet94].
The kinetic constants reported below were measured in the presence of 6.5 µM UDP-N-acetylmuramyl-L-Ala [Ho95].
Primary Physiological Regulators of Enzyme Activity: UDP-N-acetyl-α-D-muramoyl-L-alanine
T(opt): 37 °C [Doublet94]
pH(opt): 7.8 [Doublet94]
Peter D. Karp on Wed Jan 18, 2006:
Gene left-end position adjusted based on analysis performed in the 2005 E. coli annotation update [Riley06 ].
10/20/97 Gene b3967 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11204; confirmed by SwissProt match.
Ashiuchi95: Ashiuchi M, Yoshimura T, Kitamura T, Kawata Y, Nagai J, Gorlatov S, Esaki N, Soda K (1995). "In vivo effect of GroESL on the folding of glutamate racemase of Escherichia coli." J Biochem 117(3);495-8. PMID: 7629013
Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554
Doublet92: Doublet P, van Heijenoort J, Mengin-Lecreulx D (1992). "Identification of the Escherichia coli murI gene, which is required for the biosynthesis of D-glutamic acid, a specific component of bacterial peptidoglycan." J Bacteriol 1992;174(18);5772-9. PMID: 1355768
Doublet93: Doublet P, van Heijenoort J, Bohin JP, Mengin-Lecreulx D (1993). "The murI gene of Escherichia coli is an essential gene that encodes a glutamate racemase activity." J Bacteriol 1993;175(10);2970-9. PMID: 8098327
Doublet94: Doublet P, van Heijenoort J, Mengin-Lecreulx D (1994). "The glutamate racemase activity from Escherichia coli is regulated by peptidoglycan precursor UDP-N-acetylmuramoyl-L-alanine." Biochemistry 33(17);5285-90. PMID: 8172902
Doublet96: Doublet P, van Heijenoort J, Mengin-Lecreulx D (1996). "Regulation of the glutamate racemase of Escherichia coli investigated by site-directed mutagenesis." Microb Drug Resist 2(1);43-9. PMID: 9158721
Dougherty93: Dougherty TJ, Thanassi JA, Pucci MJ (1993). "The Escherichia coli mutant requiring D-glutamic acid is the result of mutations in two distinct genetic loci." J Bacteriol 175(1);111-6. PMID: 8093236
Ho95: Ho HT, Falk PJ, Ervin KM, Krishnan BS, Discotto LF, Dougherty TJ, Pucci MJ (1995). "UDP-N-acetylmuramyl-L-alanine functions as an activator in the regulation of the Escherichia coli glutamate racemase activity." Biochemistry 1995;34(8);2464-70. PMID: 7873525
Hufton95: Hufton SE, Ward RJ, Bunce NA, Armstrong JT, Fletcher AJ, Glass RE (1995). "Structure-function analysis of the vitamin B12 receptor of Escherichia coli by means of informational suppression." Mol Microbiol 15(2);381-93. PMID: 7746157
Kim00c: Kim WC, Rhee HI, Park BK, Suk KH, Cha SH (2000). "Isolation of peptide ligands that inhibit glutamate racemase activity from a random phage display library." J Biomol Screen 5(6);435-40. PMID: 11598461
Liu98a: Liu L, Yoshimura T, Endo K, Kishimoto K, Fuchikami Y, Manning JM, Esaki N, Soda K (1998). "Compensation for D-glutamate auxotrophy of Escherichia coli WM335 by D-amino acid aminotransferase gene and regulation of murI expression." Biosci Biotechnol Biochem 62(1);193-5. PMID: 9501533
Lundqvist07: Lundqvist T, Fisher SL, Kern G, Folmer RH, Xue Y, Newton DT, Keating TA, Alm RA, de Jonge BL (2007). "Exploitation of structural and regulatory diversity in glutamate racemases." Nature 447(7146);817-22. PMID: 17568739
Pucci94: Pucci MJ, Novotny J, Discotto LF, Dougherty TJ (1994). "The Escherichia coli Dga (MurI) protein shares biological activity and structural domains with the Pediococcus pentosaceus glutamate racemase." J Bacteriol 176(2);528-30. PMID: 7904596
Riley06: Riley M, Abe T, Arnaud MB, Berlyn MK, Blattner FR, Chaudhuri RR, Glasner JD, Horiuchi T, Keseler IM, Kosuge T, Mori H, Perna NT, Plunkett G, Rudd KE, Serres MH, Thomas GH, Thomson NR, Wishart D, Wanner BL (2006). "Escherichia coli K-12: a cooperatively developed annotation snapshot--2005." Nucleic Acids Res 34(1);1-9. PMID: 16397293
Yoshimura93: Yoshimura T, Ashiuchi M, Esaki N, Kobatake C, Choi SY, Soda K (1993). "Expression of glr (murI, dga) gene encoding glutamate racemase in Escherichia coli." J Biol Chem 268(32);24242-6. PMID: 7901215
Aufrere86: Aufrere R, Tempete M, Bohin JP (1986). "Regulation of expression of the gene for vitamin B12 receptor cloned on a multicopy plasmid in Escherichia coli." Mol Gen Genet 1986;205(2);358-65. PMID: 3027510
Gallo08: Gallo S, Oberhuber M, Sigel RK, Krautler B (2008). "The Corrin Moiety of Coenzyme B(12) is the Determinant for Switching the btuB Riboswitch of E. coli." Chembiochem 9(9):1408-14. PMID: 18506875
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