This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Generation of Precursor Metabolites and Energy → Electron Transfer|
|Generation of Precursor Metabolites and Energy → Respiration → Anaerobic Respiration|
Some taxa known to possess this pathway include : Escherichia coli K-12 substr. MG1655
Expected Taxonomic Range: Bacteria
Like fermentation, respiration is a process by which electrons are passed from an electron donor to a terminal electron acceptor. However, in respiration the electrons do not pass directly from the donor to the acceptor. Instead, they pass a number of membrane-bound electron carriers that function as a transport chain, passing the electrons from one to another in steps that follow the electrochemical gradients between the electron donor and the acceptor.
Each oxidized member of the electron transfer chain (which can be a flavoprotein, an electron-transfer quinone, a cytochrome, or other type of electron carrier) can be reduced by the reduced form of the preceding member, and the electrons flow through the chain all the way to the terminal acceptor, which could be oxygen in the case of aerobic respiration, or another type of molecule in anaerobic respiration.
Known terminal acceptors include organic compounds (fumarate, dimethyl sulfoxide, or trimethylamine N-oxide), or inorganic compounds (nitrate, nitrite, nitrous oxide, chlorate, perchlorate, oxidized manganese ions, ferric iron, gold, selenate, arsenate, sulfate and elemental sulfur).
During the process of electron transfer, a proton gradient is formed across the membrane due to three potential processes:
1. The use of some of the energy associated with the electron transfer for active pumping of protons out of the cell.
2. Exporting protons out of the cell during electron-to-hydrogen transfers.
3. Scalar reactions that consume protons inside the cell, or produce them outside the cell, without actually moving a proton from one compartment to another.
Upon passage of protons back into the cytoplasm, they drive multisubunit ATP synthase enzymes that generate ATP.
About This Pathway
In the Escherichia coli respiratory chain formed by NADH dehydrogenase I (NDH-1) and dimethyl sulfoxide (DMSO) reductase the transfer of electrons from NADH to DMSO is coupled to the generation of a proton-motive force across the cytoplasmic membrane.
Two electrons are transferred from the NADH oxidation site to the DMSO reduction site by a menaquinone pool. The number of protons pumped across the membrane by NDH-1 is currently unknown [Yagi03] however the H+/e- ratio for NDH-1 is at least 1.5 [Bogachev96]. DMSO reductase does not catalyse vectorial proton translocation however the reduction of the DMSO and many other amine-N-oxides and methyl-sulfoxides, including trimethylamine N-oxide (TMAO), contributes two protons to the proton-motive force.
DMSO reductase is functionally similar to the TMAO reductases but genetically distinct [Bilous88]. This enzyme functions under anaerobic conditions and in the absence of nitrate (a preferred electron acceptor) [Cotter89]. DMSO is the preferred substrate for this enzyme [Weiner88].
Unification Links: EcoCyc:PWY0-1348
Bogachev96: Bogachev AV, Murtazina RA, Skulachev VP (1996). "H+/e- stoichiometry for NADH dehydrogenase I and dimethyl sulfoxide reductase in anaerobically grown Escherichia coli cells." J Bacteriol 178(21);6233-7. PMID: 8892824
Weiner88: Weiner JH, MacIsaac DP, Bishop RE, Bilous PT (1988). "Purification and properties of Escherichia coli dimethyl sulfoxide reductase, an iron-sulfur molybdoenzyme with broad substrate specificity." J Bacteriol 1988;170(4);1505-10. PMID: 3280546
Al12: Al Mamun AA, Lombardo MJ, Shee C, Lisewski AM, Gonzalez C, Lin D, Nehring RB, Saint-Ruf C, Gibson JL, Frisch RL, Lichtarge O, Hastings PJ, Rosenberg SM (2012). "Identity and function of a large gene network underlying mutagenic repair of DNA breaks." Science 338(6112);1344-8. PMID: 23224554
Amarneh03: Amarneh B, Vik SB (2003). "Mutagenesis of subunit N of the Escherichia coli complex I. Identification of the initiation codon and the sensitivity of mutants to decylubiquinone." Biochemistry 42(17);4800-8. PMID: 12718520
Arifuzzaman06: Arifuzzaman M, Maeda M, Itoh A, Nishikata K, Takita C, Saito R, Ara T, Nakahigashi K, Huang HC, Hirai A, Tsuzuki K, Nakamura S, Altaf-Ul-Amin M, Oshima T, Baba T, Yamamoto N, Kawamura T, Ioka-Nakamichi T, Kitagawa M, Tomita M, Kanaya S, Wada C, Mori H (2006). "Large-scale identification of protein-protein interaction of Escherichia coli K-12." Genome Res 16(5);686-91. PMID: 16606699
Auriol11: Auriol C, Bestel-Corre G, Claude JB, Soucaille P, Meynial-Salles I (2011). "Stress-induced evolution of Escherichia coli points to original concepts in respiratory cofactor selectivity." Proc Natl Acad Sci U S A 108(4);1278-83. PMID: 21205901
Baranova07: Baranova EA, Morgan DJ, Sazanov LA (2007). "Single particle analysis confirms distal location of subunits NuoL and NuoM in Escherichia coli complex I." J Struct Biol 159(2);238-42. PMID: 17360196
Baranova07a: Baranova EA, Holt PJ, Sazanov LA (2007). "Projection structure of the membrane domain of Escherichia coli respiratory complex I at 8 A resolution." J Mol Biol 366(1);140-54. PMID: 17157874
Belevich07: Belevich G, Euro L, Wikstrom M, Verkhovskaya M (2007). "Role of the conserved arginine 274 and histidine 224 and 228 residues in the NuoCD subunit of complex I from Escherichia coli." Biochemistry 46(2);526-33. PMID: 17209562
Belevich11: Belevich G, Knuuti J, Verkhovsky MI, Wikstrom M, Verkhovskaya M (2011). "Probing the mechanistic role of the long α-helix in subunit L of respiratory Complex I from Escherichia coli by site-directed mutagenesis." Mol Microbiol 82(5);1086-95. PMID: 22060017
Berrisford08: Berrisford JM, Thompson CJ, Sazanov LA (2008). "Chemical and NADH-induced, ROS-dependent, cross-linking between subunits of complex I from Escherichia coli and Thermus thermophilus." Biochemistry 47(39);10262-70. PMID: 18771280
Bilous88a: Bilous PT, Cole ST, Anderson WF, Weiner JH (1988). "Nucleotide sequence of the dmsABC operon encoding the anaerobic dimethylsulphoxide reductase of Escherichia coli." Mol Microbiol 2(6);785-95. PMID: 3062312
Bongaerts95: Bongaerts J, Zoske S, Weidner U, Unden G (1995). "Transcriptional regulation of the proton translocating NADH dehydrogenase genes (nuoA-N) of Escherichia coli by electron acceptors, electron donors and gene regulators." Mol Microbiol 16(3);521-34. PMID: 7565112
Bottcher02: Bottcher B, Scheide D, Hesterberg M, Nagel-Steger L, Friedrich T (2002). "A novel, enzymatically active conformation of the Escherichia coli NADH:ubiquinone oxidoreductase (complex I)." J Biol Chem 277(20);17970-7. PMID: 11880370
Braun98: Braun M, Bungert S, Friedrich T (1998). "Characterization of the overproduced NADH dehydrogenase fragment of the NADH:ubiquinone oxidoreductase (complex I) from Escherichia coli." Biochemistry 37(7);1861-7. PMID: 9485311
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