Biomaterial Database

Direct transfer of NADH from malate dehydrogenase to complex I in Escherichia coli. 2005

Bilal Amarneh, and Steven B Vik

Department of Biophysics and Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.

During aerobic growth of Escherichia coli, nicotinamide adenine dinucleotide (NADH) can initiate electron transport at either of two sites: Complex I (NDH-1 or NADH:ubiquinone oxidoreductase) or a single-subunit NADH dehydrogenase (NDH-2). We report evidence for the specific coupling of malate dehydrogenase to Complex I. Membrane vesicles prepared from wild type cultures retain malate dehydrogenase and are capable of proton translocation driven by the addition of malate + NAD. This activity was inhibited by capsaicin, an inhibitor specific to Complex I, and it proceeded with deamino-NAD, a substrate utilized by Complex I, but not by NDH-2. The concentration of free NADH produced by membrane vesicles supplemented with malate + NAD was estimated to be 1 microM, while the rate of proton translocation due to Complex I was consistent with a somewhat higher concentration, suggesting a direct transfer mechanism. This interpretation was supported by competition assays in which inactive mutant forms of malate dehydrogenase were able to inhibit Complex I activity. These two lines of evidence indicate that the direct transfer of NADH from malate dehydrogenase to Complex I can occur in the E. coli system.

UI	MeSH Term	Description	Entries
D008291	Malate Dehydrogenase	An enzyme that catalyzes the conversion of (S)-malate and NAD+ to oxaloacetate and NADH. EC 1.1.1.37.	Malic Dehydrogenase,NAD-Malate Dehydrogenase,Dehydrogenase, Malate,Dehydrogenase, Malic,Dehydrogenase, NAD-Malate,NAD Malate Dehydrogenase
D009097	Multienzyme Complexes	Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES.	Complexes, Multienzyme
D009243	NAD	A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)	Coenzyme I,DPN,Diphosphopyridine Nucleotide,Nadide,Nicotinamide-Adenine Dinucleotide,Dihydronicotinamide Adenine Dinucleotide,NADH,Adenine Dinucleotide, Dihydronicotinamide,Dinucleotide, Dihydronicotinamide Adenine,Dinucleotide, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide,Nucleotide, Diphosphopyridine
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, Protein
D004579	Electron Transport	The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)	Respiratory Chain,Chain, Respiratory,Chains, Respiratory,Respiratory Chains,Transport, Electron
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D042967	Electron Transport Complex I	A flavoprotein and iron sulfur-containing oxidoreductase complex that catalyzes the conversion of UBIQUINONE to ubiquinol. In MITOCHONDRIA the complex also couples its reaction to the transport of PROTONS across the internal mitochondrial membrane. The NADH DEHYDROGENASE component of the complex can be isolated and is listed as EC 1.6.99.3.	NADH Dehydrogenase (Ubiquinone),Complex I Dehydrogenase,NADH DH I,NADH Dehydrogenase Complex 1,NADH Dehydrogenase I,NADH Q1 Oxidoreductase,NADH-CoQ Reductase,NADH-Coenzyme Q Reductase,NADH-Ubiquinone Oxidoreductase,NADH-Ubiquinone Reductase,Respiratory Complex I,Rotenone-Sensitive Mitochondrial NADH-Ubiquinone Oxidoreductase,Ubiquinone Reductase,Dehydrogenase, Complex I,NADH CoQ Reductase,NADH Coenzyme Q Reductase,NADH Ubiquinone Oxidoreductase,NADH Ubiquinone Reductase,Oxidoreductase, NADH Q1,Oxidoreductase, NADH-Ubiquinone,Reductase, NADH-Ubiquinone,Rotenone Sensitive Mitochondrial NADH Ubiquinone Oxidoreductase
D021962	Membrane Microdomains	Detergent-insoluble CELL MEMBRANE components. They are enriched in SPHINGOLIPIDS and CHOLESTEROL and clustered with glycosyl-phosphatidylinositol (GPI)-anchored proteins.	Lipid Rafts, Cell Membrane,Sphingolipid Microdomains,Sphingolipid-Cholesterol Rafts,Membrane Microdomain,Microdomain, Membrane,Microdomain, Sphingolipid,Microdomains, Membrane,Microdomains, Sphingolipid,Sphingolipid Cholesterol Rafts,Sphingolipid Microdomain,Sphingolipid-Cholesterol Raft