Enzymes
| UniProtKB help_outline | 4 proteins |
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- Name help_outline Nα-acetyl-D-methionine Identifier CHEBI:85220 Charge -1 Formula C7H12NO3S InChIKeyhelp_outline XUYPXLNMDZIRQH-ZCFIWIBFSA-M SMILEShelp_outline CSCC[C@@H](NC(C)=O)C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 1 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline Nα-acetyl-L-methionine Identifier CHEBI:71670 Charge -1 Formula C7H12NO3S InChIKeyhelp_outline XUYPXLNMDZIRQH-LURJTMIESA-M SMILEShelp_outline CSCC[C@H](NC(C)=O)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
Cross-references
| RHEA:59960 | RHEA:59961 | RHEA:59962 | RHEA:59963 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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Publications
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Structural basis for catalytic racemization and substrate specificity of an N-acylamino acid racemase homologue from Deinococcus radiodurans.
Wang W.C., Chiu W.C., Hsu S.K., Wu C.L., Chen C.Y., Liu J.S., Hsu W.H.
N-acylamino acid racemase (NAAAR) catalyzes the racemization of N-acylamino acids and can be used in concert with an aminoacylase to produce enantiopure alpha-amino acids, a process that has potential industrial applications. Here we have cloned and characterized an NAAAR homologue from a radiatio ... >> More
N-acylamino acid racemase (NAAAR) catalyzes the racemization of N-acylamino acids and can be used in concert with an aminoacylase to produce enantiopure alpha-amino acids, a process that has potential industrial applications. Here we have cloned and characterized an NAAAR homologue from a radiation-resistant ancient bacterium, Deinococcus radiodurans. The expressed NAAAR racemized various substrates at an optimal temperature of 60 degrees C and had Km values of 24.8 mM and 12.3 mM for N-acetyl-D-methionine and N-acetyl-L-methionine, respectively. The crystal structure of NAAAR was solved to 1.3 A resolution using multiwavelength anomalous dispersion (MAD) methods. The structure consists of a homooctamer in which each subunit has an architecture characteristic of enolases with a capping domain and a (beta/alpha)7 beta barrel domain. The NAAAR.Mg2+ and NAAAR.N-acetyl-L-glutamine.Mg2+ structures were also determined, allowing us to define the Lys170-Asp195-Glu220-Asp245-Lys269 framework for catalyzing 1,1-proton exchange of N-acylamino acids. Four subsites enclosing the substrate are identified: catalytic site, metal-binding site, side-chain-binding region, and a flexible lid region. The high conservation of catalytic and metal-binding sites in different enolases reflects the essentiality of a common catalytic platform, allowing these enzymes to robustly abstract alpha-protons of various carboxylate substrates efficiently. The other subsites involved in substrate recognition are less conserved, suggesting that divergent evolution has led to functionally distinct enzymes. << Less
J. Mol. Biol. 342:155-169(2004) [PubMed] [EuropePMC]
This publication is cited by 4 other entries.
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Structure-stability-activity relationship in covalently cross-linked N-carbamoyl D-amino acid amidohydrolase and N-acylamino acid racemase.
Chiu W.C., You J.Y., Liu J.S., Hsu S.K., Hsu W.H., Shih C.H., Hwang J.K., Wang W.C.
N-Acylamino acid racemase (NAAAR) and N-carbamoyl-D-amino-acid amidohydrolase (D-NCAase) are important biocatalysts for producing enantiopure alpha-amino acids. NAAAR forms an octameric assembly and displays induced fit movements upon substrate binding, while D-NCAase is a tetramer that does not c ... >> More
N-Acylamino acid racemase (NAAAR) and N-carbamoyl-D-amino-acid amidohydrolase (D-NCAase) are important biocatalysts for producing enantiopure alpha-amino acids. NAAAR forms an octameric assembly and displays induced fit movements upon substrate binding, while D-NCAase is a tetramer that does not change conformation in the presence of a ligand. To investigate the effects of introducing potentially stabilizing S-S bridges in these different multimeric enzymes, cysteine residues predicted to form inter or intra-subunit disulfide bonds were introduced by site-directed mutagenesis. Inter-subunit S-S bonds were formed in two NAAAR variants (A68C-D72C and P60C-Y100C) and two d-NCAase variants (A302C and P295C-F304C). Intra-subunit S-S bonds were formed in two additional NAAAR variants (E149C-A182C and V265C). Crystal structures of NAAARs variants show limited deviations from the wild-type overall tertiary structure. An apo A68C-D72C subunit differs from the wild-type enzyme, in which it has an ordered lid loop, resembling ligand-bound NAAAR. The structures of A222C and A302C D-NCAases are nearly identical to the wild-type enzyme. All mutants with inter-subunit bridges had increases in thermostability. Compared with the wild-type enzyme, A68C-D72C NAAAR showed similar kcat/Km ratios, whereas mutant D-NCAases demonstrated increased kcat/Km ratios at high temperatures (A302C: 4.2-fold at 65 degrees C). Furthermore, molecular dynamic simulations reveal that A302C substantially sustains the fine-tuned catalytic site as temperature increases, achieving enhanced activity. << Less
J. Mol. Biol. 359:741-753(2006) [PubMed] [EuropePMC]
This publication is cited by 1 other entry.