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Escherichia coli K-12 substr. MG1655 Enzyme: NADPH quinone reductase

Gene: mdaB Accession Numbers: EG12656 (EcoCyc), b3028, ECK3019

Synonyms: mda66

Regulation Summary Diagram

Regulation summary diagram for mdaB

Subunit composition of NADPH quinone reductase = [MdaB]2
         NADPH quinone reductase monomer = MdaB

The MdaB quinone reductase is specific for NADPH and is most active with quinone derivatives and ferricyanide as electron acceptors [Hayashi96a]. In vitro, YgiN is able to reoxidize menadiol that has been reduced by MdaB quinone reductase; the two enzymes may form a quinone redox cycle. The biological role of a quinone redox cycle may be to maintain an intracellular pool of menadione and ubiquinone using a catalytic mechanism that avoids the formation of a semiquinone intermediate, and to act as a quinone buffer [Adams05a].

Despite the different cofactor and cosubstrate requirements, it was later stated that MdaB is identical to NADH dehydrogenase (quinone) [Adams05a], but no evidence was given. Unlike MdaB, NADH dehydrogenase (quinone) was shown to utilize NADH and to be FMN-dependent [Hayashi90]. Menadione specifically induces expression of the NADH- and FMN-dependent activity, while 2-methylene-4-butyrolactone (MBL) and other compounds containing a methide group induce expression of the NADPH-dependent MdaB activity [Hayashi96a].

Crystal structures of apo-MdaB and in complex with FAD have been solved [Adams05b, Adams06].

Overexpression of mdaB leads to increased resistance to the tumoricidal agent DMP 840 [Chatterjee95]. A strain adapted for growth in benzalkonium chloride overexpresses MdaB [Bore07]. An mdaB null mutant shows no change in sensitivity to menadione-induced oxidative stress [Adams06].

MdaB: "modulator of drug activity B" [Chatterjee95]

Locations: cytosol

Map Position: [3,170,552 -> 3,171,133] (68.34 centisomes, 246°)
Length: 582 bp / 193 aa

Molecular Weight of Polypeptide: 21.891 kD (from nucleotide sequence), 21 kD (experimental) [Hayashi96a ]

Molecular Weight of Multimer: 42 kD (experimental) [Hayashi96a]

Unification Links: ASAP:ABE-0009946, EchoBASE:EB2524, EcoGene:EG12656, EcoliWiki:b3028, ModBase:P0AEY5, OU-Microarray:b3028, PortEco:mdaB, PR:PRO_000023173, Pride:P0AEY5, Protein Model Portal:P0AEY5, RefSeq:NP_417500, RegulonDB:EG12656, SMR:P0AEY5, String:511145.b3028, UniProt:P0AEY5

Relationship Links: InterPro:IN-FAMILY:IPR003680, InterPro:IN-FAMILY:IPR029039, PDB:Structure:2B3D, Pfam:IN-FAMILY:PF02525

In Paralogous Gene Group: 18 (3 members)

Gene-Reaction Schematic

Gene-Reaction Schematic

GO Terms:
Biological Process:
Inferred from experimentGO:0055114 - oxidation-reduction process [Hayashi96a]
Molecular Function:
Inferred from experimentGO:0008753 - NADPH dehydrogenase (quinone) activity [Hayashi96a]
Inferred from experimentGO:0050660 - flavin adenine dinucleotide binding [Adams06]
Cellular Component:
Inferred from experimentGO:0005829 - cytosol [Ishihama08]

MultiFun Terms: cell processesprotectiondrug resistance/sensitivity
metabolismenergy production/transportelectron donors

Essentiality data for mdaB knockouts:

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enrichedYes 37 Aerobic 6.95   Yes [Gerdes03, Comment 1]
LB LennoxYes 37 Aerobic 7   Yes [Baba06, Comment 2]
M9 medium with 1% glycerolYes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 3]
MOPS medium with 0.4% glucoseYes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 2]
Yes [Feist07, Comment 4]

Last-Curated 22-Apr-2010 by Keseler I, SRI International

Enzymatic reaction of: NADPH quinone reductase

Inferred from experiment

Synonyms: NADPH-specific quinone reductase, NADPH dehydrogenase (quinone), NADPH:(quinone-acceptor) oxidoreductase

EC Number:

Transport reaction diagram for NADPH quinone reductase

Alternative Substrates for an electron-transfer quinone: 1,4-benzoquinone [Hayashi96a], ferricyanide [Hayashi96a], 1,4-naphthoquinone [Hayashi96a], menadione [Hayashi96a]

Amino-terminal sequence determination of the purified enzyme showed it to be the product of the mdaB gene. The enzyme can be purified in two forms which differ in FAD content and charge [Hayashi96a].

Cofactors or Prosthetic Groups: FAD [Hayashi96a]

Kinetic Parameters:
Substrate Km (μM) Citations
NADPH 10.4 [Hayashi96a]

pH(opt): 7 [Hayashi96a]

Sequence Features

Protein sequence of NADPH quinone reductase monomer with features indicated

Feature Class Location Citations Comment
Cleavage-of-Initial-Methionine 1
Inferred from experiment[Hayashi96a]
Pfam PF02525 3 -> 188
Inferred by computational analysis[Finn14]
Flavodoxin_2 : Flavodoxin-like fold

Gene Local Context (not to scale -- see Genome Browser for correct scale)

Gene local context diagram

Transcription Unit

Transcription-unit diagram


10/20/97 Gene b3028 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG12656; confirmed by SwissProt match.


Adams05a: Adams MA, Jia Z (2005). "Structural and biochemical evidence for an enzymatic quinone redox cycle in Escherichia coli: identification of a novel quinol monooxygenase." J Biol Chem 280(9);8358-63. PMID: 15613473

Adams05b: Adams MA, Iannuzzi P, Jia Z (2005). "MdaB from Escherichia coli: cloning, purification, crystallization and preliminary X-ray analysis." Acta Crystallograph Sect F Struct Biol Cryst Commun 61(Pt 2);235-8. PMID: 16511004

Adams06: Adams MA, Jia Z (2006). "Modulator of drug activity B from Escherichia coli: crystal structure of a prokaryotic homologue of DT-diaphorase." J Mol Biol 359(2);455-65. PMID: 16630630

Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554

Bore07: Bore E, Hebraud M, Chafsey I, Chambon C, Skjaeret C, Moen B, Moretro T, Langsrud O, Rudi K, Langsrud S (2007). "Adapted tolerance to benzalkonium chloride in Escherichia coli K-12 studied by transcriptome and proteome analyses." Microbiology 153(Pt 4);935-46. PMID: 17379704

Chatterjee95: Chatterjee PK, Sternberg NL (1995). "A general genetic approach in Escherichia coli for determining the mechanism(s) of action of tumoricidal agents: application to DMP 840, a tumoricidal agent." Proc Natl Acad Sci U S A 92(19);8950-4. PMID: 7568050

Feist07: Feist AM, Henry CS, Reed JL, Krummenacker M, Joyce AR, Karp PD, Broadbelt LJ, Hatzimanikatis V, Palsson BO (2007). "A genome-scale metabolic reconstruction for Escherichia coli K-12 MG1655 that accounts for 1260 ORFs and thermodynamic information." Mol Syst Biol 3;121. PMID: 17593909

Finn14: Finn RD, Bateman A, Clements J, Coggill P, Eberhardt RY, Eddy SR, Heger A, Hetherington K, Holm L, Mistry J, Sonnhammer EL, Tate J, Punta M (2014). "Pfam: the protein families database." Nucleic Acids Res 42(Database issue);D222-30. PMID: 24288371

Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938

Hayashi90: Hayashi M, Hasegawa K, Oguni Y, Unemoto T (1990). "Characterization of FMN-dependent NADH-quinone reductase induced by menadione in Escherichia coli." Biochim Biophys Acta 1990;1035(2);230-6. PMID: 2118386

Hayashi96a: Hayashi M, Ohzeki H, Shimada H, Unemoto T (1996). "NADPH-specific quinone reductase is induced by 2-methylene-4-butyrolactone in Escherichia coli." Biochim Biophys Acta 1273(2);165-70. PMID: 8611590

Ishihama08: Ishihama Y, Schmidt T, Rappsilber J, Mann M, Hartl FU, Kerner MJ, Frishman D (2008). "Protein abundance profiling of the Escherichia coli cytosol." BMC Genomics 9;102. PMID: 18304323

Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394

Other References Related to Gene Regulation

Martin11a: Martin RG, Rosner JL (2011). "Promoter discrimination at class I MarA regulon promoters mediated by glutamic acid 89 of the MarA transcriptional activator of Escherichia coli." J Bacteriol 193(2);506-15. PMID: 21097628

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by Pathway Tools version 19.5 (software by SRI International) on Sat Apr 30, 2016, biocyc13.