Enzymes
| UniProtKB help_outline | 4,292 proteins |
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- Name help_outline acetyl-CoA Identifier CHEBI:57288 (Beilstein: 8468140) help_outline Charge -4 Formula C23H34N7O17P3S InChIKeyhelp_outline ZSLZBFCDCINBPY-ZSJPKINUSA-J SMILEShelp_outline CC(=O)SCCNC(=O)CCNC(=O)[C@H](O)C(C)(C)COP([O-])(=O)OP([O-])(=O)OC[C@H]1O[C@H]([C@H](O)[C@@H]1OP([O-])([O-])=O)n1cnc2c(N)ncnc12 2D coordinates Mol file for the small molecule Search links Involved in 352 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline L-2,4-diaminobutanoate Identifier CHEBI:58761 Charge 1 Formula C4H11N2O2 InChIKeyhelp_outline OGNSCSPNOLGXSM-VKHMYHEASA-O SMILEShelp_outline [NH3+]CC[C@H]([NH3+])C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 5 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline (2S)-4-acetamido-2-aminobutanoate Identifier CHEBI:58929 Charge 0 Formula C6H12N2O3 InChIKeyhelp_outline YLZRFVZUZIJABA-YFKPBYRVSA-N SMILEShelp_outline CC(=O)NCC[C@H]([NH3+])C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline CoA Identifier CHEBI:57287 (Beilstein: 11604429) help_outline Charge -4 Formula C21H32N7O16P3S InChIKeyhelp_outline RGJOEKWQDUBAIZ-IBOSZNHHSA-J SMILEShelp_outline CC(C)(COP([O-])(=O)OP([O-])(=O)OC[C@H]1O[C@H]([C@H](O)[C@@H]1OP([O-])([O-])=O)n1cnc2c(N)ncnc12)[C@@H](O)C(=O)NCCC(=O)NCCS 2D coordinates Mol file for the small molecule Search links Involved in 1,500 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,431 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:16901 | RHEA:16902 | RHEA:16903 | RHEA:16904 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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Cloning, purification, and characterization of diaminobutyrate acetyltransferase from the halotolerant methanotroph Methylomicrobium alcaliphilum 20Z.
Reshetnikov A.S., Mustakhimov I.I., Khmelenina V.N., Trotsenko Y.A.
L-2,4-Diaminobutyrate (DAB) acetyltransferase (DABAcT) catalyzes one of the key reactions of biosynthesis of the bacterial osmoprotectant ectoine--acetylation of L-2,4-DAB yielding Ngamma-acetyl-2,4-DAB. Gene ectA encoding DABAcT was cloned from DNA of the halotolerant methanotroph Methylomicrobiu ... >> More
L-2,4-Diaminobutyrate (DAB) acetyltransferase (DABAcT) catalyzes one of the key reactions of biosynthesis of the bacterial osmoprotectant ectoine--acetylation of L-2,4-DAB yielding Ngamma-acetyl-2,4-DAB. Gene ectA encoding DABAcT was cloned from DNA of the halotolerant methanotroph Methylomicrobium alcaliphilum 20Z and expressed in Escherichia coli with an additional six His residues at the C-terminus. Homogeneous enzyme preparation with specific activity 200 U/mg was obtained by affinity metal-chelating chromatography. DABAcT was found to be a homodimer with molecular mass 40 kD. The enzyme is most active at pH 9.5 and 20 degrees C, and its activity increased threefold in the presence of 0.1-0.2 M NaCl or 0.2 M KCl. The Km values of recombinant DABAcT measured at the optimal pH and temperature in the presence of 0.2 M KCl were 460 and 36.6 microM for L-2,4-DAB and acetyl-CoA, respectively. The enzyme is specific for L-2,4-DAB and acetyl-CoA and is also active against propionyl-CoA (20%). Zn2+ and Cd2+ at 1 mM concentration completely inhibit the recombinant enzyme; 10 mM ATP inhibits 26% of the enzyme activity, whereas EDTA, o-phenanthroline, ADP, NAD(P), and NAD(P)H do not significantly effect the enzyme activity. The possible participation of DABAcT in regulation of ectoine biosynthesis in M. alcaliphilum 20Z is discussed. << Less
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Characterization of the recombinant diaminobutyric acid acetyltransferase from Methylophaga thalassica and Methylophaga alcalica.
Mustakhimov I.I., Rozova O.N., Reshetnikov A.S., Khmelenina V.N., Murrell J.C., Trotsenko Y.A.
Diaminobutyric acid acetyltransferase (EctA) catalyzes the acetylation of diaminobutyric acid to gamma-N-acetyl-alpha,gamma-diaminobutyrate with acetyl coenzyme A. This is the second reaction in the ectoine biosynthetic pathway. The recombinant EctA proteins were purified from two moderately halop ... >> More
Diaminobutyric acid acetyltransferase (EctA) catalyzes the acetylation of diaminobutyric acid to gamma-N-acetyl-alpha,gamma-diaminobutyrate with acetyl coenzyme A. This is the second reaction in the ectoine biosynthetic pathway. The recombinant EctA proteins were purified from two moderately halophilic methylotrophic bacteria: Methylophaga thalassica ATCC 33146T and Methylophaga alcalica ATCC 35842T. EctA found in both methylotrophs is a homodimer with a subunit molecular mass of c. 20 kDa and had similar properties with respect to the optimum temperature for activity (30 degrees C), Km for diaminobutyrate (370 or 375 microM) and the absence of requirements for divalent metal ions. The enzyme from M. thalassica exhibited a lower pH optimum and was inhibited both by sodium carbonates and by high ionic strength but to a lesser extent by copper ions. << Less
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Characterization of genes for the biosynthesis of the compatible solute ectoine from Marinococcus halophilus and osmoregulated expression in Escherichia coli.
Louis P., Galinski E.A.
The genes of the biosynthetic pathway of ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) from the Gram-positive moderate halophile Marinococcus halophilus were cloned by functional expression in Escherichia coli. These genes were not only expressed, but also osmoregulated in E. c ... >> More
The genes of the biosynthetic pathway of ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) from the Gram-positive moderate halophile Marinococcus halophilus were cloned by functional expression in Escherichia coli. These genes were not only expressed, but also osmoregulated in E. coli, as demonstrated by increasing cytoplasmic ectoine concentration in response to medium salinity. Sequencing of a 4.4 kb fragment revealed four major ORFs, which were designated ectA, ectB, ectC and orfA. The significance of three of these genes for ectoine synthesis was proved by sequence comparison with known proteins and by physiological experiments. Several deletion derivatives of the sequenced fragment were introduced into E. coli and the resulting clones were investigated for their ability to synthesize ectoine or one of the intermediates in its biosynthetic pathway. It was demonstrated that ectA codes for L-2,4-diaminobutyric acid acetyltransferase, ectB for L-2,4-diaminobutyric acid transaminase and ectC for L-ectoine synthase. A DNA region upstream of ectA was shown to be necessary for the regulated expression of ectoine synthesis in response to the osmolarity of the medium. << Less
Microbiology 143:1141-1149(1997) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.
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Characterization of the ectoine biosynthesis genes of haloalkalotolerant obligate methanotroph 'Methylomicrobium alcaliphilum 20Z'.
Reshetnikov A.S., Khmelenina V.N., Trotsenko Y.A.
The genes involved in biosynthesis of the major compatible solute ectoine (1,4,5,6-tetrahydro-2-methylpyrimidine carboxylic acid) in halotolerant obligate methanotroph "Methylomicrobium alcaliphilum 20Z" were studied. The complete nucleotide sequences of the structural genes encoding L: -aspartoki ... >> More
The genes involved in biosynthesis of the major compatible solute ectoine (1,4,5,6-tetrahydro-2-methylpyrimidine carboxylic acid) in halotolerant obligate methanotroph "Methylomicrobium alcaliphilum 20Z" were studied. The complete nucleotide sequences of the structural genes encoding L: -aspartokinase (Ask), L-2,4-diaminobutyric acid transaminase (EctB), L-2,4-diaminobutyric acid acetyltransferase (EctA), and L-ectoine synthase (EctC) were defined and shown to be transcribed as a single operon ectABCask. Phylogenetic analysis revealed high sequence identities (34-63%) of the Ect proteins to those from halophilic heterotrophs with the highest amino acid identities being to Vibrio cholerae enzymes. The chromosomal DNA fragment from "M. alcaliphilum 20Z" containing ectABC genes and putative promoter region was expressed in Escherichia coli. Recombinant cells could grow in the presence of 4% NaCl and synthesize ectoine. The data obtained suggested that despite the ectoine biosynthesis pathway being evolutionary well conserved with respect to the genes and enzymes involved, some differences in their organization and regulation could occur in various halophilic bacteria. << Less
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Characterization of biosynthetic enzymes for ectoine as a compatible solute in a moderately halophilic eubacterium, Halomonas elongata.
Ono H., Sawada K., Khunajakr N., Tao T., Yamamoto M., Hiramoto M., Shinmyo A., Takano M., Murooka Y.
1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) is an excellent osmoprotectant. The biosynthetic pathway of ectoine from aspartic beta-semialdehyde (ASA), in Halomonas elongata, was elucidated by purification and characterization of each enzyme involved. 2,4-Diaminobutyrate (DABA ... >> More
1,4,5,6-Tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) is an excellent osmoprotectant. The biosynthetic pathway of ectoine from aspartic beta-semialdehyde (ASA), in Halomonas elongata, was elucidated by purification and characterization of each enzyme involved. 2,4-Diaminobutyrate (DABA) aminotransferase catalyzed reversively the first step of the pathway, conversion of ASA to DABA by transamination with L-glutamate. This enzyme required pyridoxal 5'-phosphate and potassium ions for its activity and stability. The gel filtration estimated an apparent molecular mass of 260 kDa, whereas molecular mass measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was 44 kDa. This enzyme exhibited an optimum pH of 8.6 and an optimum temperature of 25 degreesC and had Kms of 9.1 mM for L-glutamate and 4.5 mM for DL-ASA. DABA acetyltransferase catalyzed acetylation of DABA to gamma-N-acetyl-alpha,gamma-diaminobutyric acid (ADABA) with acetyl coenzyme A and exhibited an optimum pH of 8.2 and an optimum temperature of 20 degreesC in the presence of 0.4 M NaCl. The molecular mass was 45 kDa by gel filtration. Ectoine synthase catalyzed circularization of ADABA to ectoine and exhibited an optimum pH of 8.5 to 9.0 and an optimum temperature of 15 degreesC in the presence of 0.5 M NaCl. This enzyme had an apparent molecular mass of 19 kDa by SDS-PAGE and a Km of 8.4 mM in the presence of 0. 77 M NaCl. DABA acetyltransferase and ectoine synthase were stabilized in the presence of NaCl (>2 M) and DABA (100 mM) at temperatures below 30 degreesC. << Less
J. Bacteriol. 181:91-99(1999) [PubMed] [EuropePMC]
This publication is cited by 2 other entries.