The enzyme, characterized from the bacterium Rhodobacter sphaeroides, is involved in the ethylmalonyl-CoA pathway for acetyl-CoA assimilation. The enzyme contains FAD.
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The expected taxonomic range for this enzyme is: Bacteria, Eukaryota
The enzyme, characterized from the bacterium Rhodobacter sphaeroides, is involved in the ethylmalonyl-CoA pathway for acetyl-CoA assimilation. The enzyme contains FAD.
the enzyme is highly specific for (S)-methylsuccinyl-CoA. No activity with butyryl-CoA, isobutyryl-CoA or a diastereomeric mixture of (R)-methylsuccinyl-CoA
FAD does not dissociate from the enzyme during catalysis. The reaction product can only be released after FAD is re-oxidized within the active site by a final electron acceptor
substrate specificity of methylsuccinyl-CoA dehydrogenase, structure-function analysis, overview. The enzyme catalyzes the oxidation of (2S)-methylsuccinyl-CoA to alpha,beta-unsaturated mesaconyl-CoA and shows only about 0.5% activity with succinyl-CoA. MCD catalyzes the unprecedented oxidation of an alpha-methyl branched dicarboxylic acid CoA thioester. Substrate specificity is achieved by a cluster of three arginines that accommodates the terminal carboxyl group and a dedicated cavity that facilitates binding of the C2 methyl branch. The alpha,beta-desaturation of the CoA thioester is initiated by a proton abstraction from the alpha-carbon by a conserved catalytically active glutamate and a hydride transfer from the beta-carbon to the N5 of the FAD cofactor. The reduced cofactor is reoxidized by two sequential one-electron transfers to electron transfer flavoproteins (ETFs), which in turn deliver the electrons to the membrane-bound electron transport chain for energy conservation
substrate specificity of methylsuccinyl-CoA dehydrogenase, structure-function analysis, overview. The enzyme catalyzes the oxidation of (2S)-methylsuccinyl-CoA to alpha,beta-unsaturated mesaconyl-CoA and shows only about 0.5% activity with succinyl-CoA. MCD catalyzes the unprecedented oxidation of an alpha-methyl branched dicarboxylic acid CoA thioester. Substrate specificity is achieved by a cluster of three arginines that accommodates the terminal carboxyl group and a dedicated cavity that facilitates binding of the C2 methyl branch. The alpha,beta-desaturation of the CoA thioester is initiated by a proton abstraction from the alpha-carbon by a conserved catalytically active glutamate and a hydride transfer from the beta-carbon to the N5 of the FAD cofactor. The reduced cofactor is reoxidized by two sequential one-electron transfers to electron transfer flavoproteins (ETFs), which in turn deliver the electrons to the membrane-bound electron transport chain for energy conservation
required prosthetic group, FAD does not dissociate from the enzyme during catalysis. The reaction product can only be released after FAD is re-oxidized within the active site by a final electron acceptor
convertion of (2S)-methylsuccinyl-CoA dehydrogenase (Mcd), a member of the ACAD enzyme family, into a (2S)-methylsuccinyl-CoA oxidase (Mco) through three active site mutations
(2S)-methylsuccinyl-CoA dehydrogenase (MCD) belongs to the family of FAD-dependent acyl-CoA dehydrogenase (ACD). Compared with other ACDs, MCD contains an about 170-residue-long N-terminal extension that structurally mimics a dimer-dimer interface of these enzymes that are canonically organized as tetramers. MCD apparently evolved toward preventing the nonspecific oxidation of succinyl-CoA, which is a close structural homologue of (2S)-methylsuccinyl-CoA and an essential intermediate in central carbon metabolism
the members of the flavin adenosine dinucleotide (FAD)-dependent acyl-CoA dehydrogenase and acyl-CoA oxidase families catalyze similar reactions and share common structural features. But both enzyme families feature opposing reaction specificities in respect to dioxygen. Dehydrogenases react with electron transfer flavoproteins as terminal electron acceptors and do not show a considerable reactivity with dioxygen, whereas dioxygen serves as a bona fide substrate for oxidases
(2S)-methylsuccinyl-CoA dehydrogenase (MCD) belongs to the family of FAD-dependent acyl-CoA dehydrogenase (ACD). Compared with other ACDs, MCD contains an about 170-residue-long N-terminal extension that structurally mimics a dimer-dimer interface of these enzymes that are canonically organized as tetramers. MCD apparently evolved toward preventing the nonspecific oxidation of succinyl-CoA, which is a close structural homologue of (2S)-methylsuccinyl-CoA and an essential intermediate in central carbon metabolism
acyl-CoA dehydrogenases (ACADs) are flavoproteins that catalyze the flavin adenosine dinucleotide (FAD)-dependent oxidation of alpha,beta-carbon bonds in acyl-CoA thioesters. ACADs are found in all kingdoms of life and are part of various metabolic pathways, such as amino acid oxidation, choline metabolism and most prominently, the initial step in fatty acid beta-oxidation. ACADs transfer the electrons from the substrate to an electron transfer flavoprotein (ETF), which in turn funnels the electrons into a membrane bound electron transport chain and from there to the final electron acceptor. The reaction of ACADs can be divided into a reductive and an oxidative half-reaction. The reductive half-reaction is initiated by abstraction of the pro-R-alpha-proton of the acyl-CoA thioester by a conserved active site glutamate. The concomitant hydride transfer of the pro-R-beta-hydrogen to the N5 atom of the isoalloxazine ring of the FAD cofactor proceeds via an enolate-like intermediate, which forms a charge-transfer complex (CTC) with the FAD. Although the substrate is rapidly converted into the CTC, no product is formed in the absence of ETF or another suitable electron acceptor The reaction is completed with the electron transfer from the CTC to ETF during the oxidative half-reaction. The oxidative half-reaction consists of two successive inter-protein one-electron transfers between reduced ACAD and two oxidized ETFs. This results in the re-oxidation of the ACAD bound FAD and yields two ETFs in the semiquinone state (ETFsq). In contrast to ACADs, acyl-CoA oxidases (ACXs) do not require an ETF partner and directly use dioxygen as a final electron acceptor
MCD prevents the nonspecific oxidation of succinyl-CoA, which is a close structural homologue of (2S)-methylsuccinyl-CoA and an essential intermediate in central carbon metabolism. Structure-function analysis, overview
MCD prevents the nonspecific oxidation of succinyl-CoA, which is a close structural homologue of (2S)-methylsuccinyl-CoA and an essential intermediate in central carbon metabolism. Structure-function analysis, overview
compared with other ACDs, MCD contains an about 170-residue-long N-terminal extension that structurally mimics a dimer-dimer interface of these enzymes that are canonically organized as tetramers
compared with other ACDs, MCD contains an about 170-residue-long N-terminal extension that structurally mimics a dimer-dimer interface of these enzymes that are canonically organized as tetramers
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CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
purified recombinant FAD-bound enzyme, sitting drop vapor diffusion method, mixing of 20 mg/ml protein in 20 mM Tris-HCl, pH 7.9, 200 mM NaCl, 1.5 mM FAD, and 3 mM mesaconyl-CoA in an 1:1 ratio with crystallization solution containing 30% PEG 5000 monomethyl ether mesylate, 100 mM Tris, pH 8.0, and 200 mM LiSO4, 16°C, X-ray diffraction structure determination and analysis at 1.37 A resolution, modeling
site-directed mutagenesis, the mutant shows increased oxidase activity and reduced dehydrogenase activity compared to wild-type. The mutant directly reacts with O2
site-directed mutagenesis, the mutant shows increased oxidase activity and reduced dehydrogenase activity compared to wild-type. The mutant directly reacts with O2
the catalytic efficiency of the variant with (2S)-methylsuccinyl-CoA is decreased by 50% compared with the wild type which is mostly due to a decreased turnover number. On the other hand, the variant exhibits an increased catalytic efficiency with unbranched succinyl-CoA due to a decrease in Km
the catalytic efficiency of the variant with (2S)-methylsuccinyl-CoA is decreased by 50% compared with the wild type which is mostly due to a decreased turnover number. On the other hand, the variant exhibits an increased catalytic efficiency with unbranched succinyl-CoA due to a decrease in Km
(2S)-methylsuccinyl-CoA dehydrogenase is engineered towards oxidase activity by rational mutagenesis. The molecular base for dioxygen reactivity in the engineered oxidase shows that the increased oxidase function of the engineered enzyme comes at a decreased dehydrogenase activity, analysis by using stopped-flow UV-spectroscopy and liquid chromatography-mass spectrometry (LC-MS) based assays. Simply increasing accessibility for dioxygen is not a straight-forward approach to increase the oxidase reactivity in ACADs. Of three single mutants W315F, T317G and E377N only the Mcd variant T317G shows significant oxidase activity. Combination of all three mutations results in a variant with considerable oxidase activity. The three residues (Y372, M375, and Y378) as targets are located in the vicinity of the FAD cofactor. M375 and Y372 cover the isoalloxazine moiety of the FAD to shield it from solvent exposure. An increased solvation of the active site is proposed to increase reactivity towards dioxygen in ACADs due to stabilization of the formed superoxide. Mutation of Y372 and M375 to isoleucine and serine, respectively, is performed because these smaller residues are partially conserved in other ACADs, according to a multiple sequence alignment
recombinant His-tagged wild-tpye and mutant enzymes from Escherichia coli strain Rosetta pLys (DE3) by nickel affinity chromatography of cell-free supernatant, desalting gel filtration, tag cleavage by thrombin, gel filtration, and ultrafiltration
recombinant His-tagged wild-type and mutant enzymes from Escherichia coli strain Rosetta (DE3) pLysS by nickel affinity chromatography and ultrafiltration