title: Pseudomonas aeruginosa MdaB and WrbA are water-soluble two-electron quinone oxidoreductases with the potential to defend against oxidative stress.
abstract: Water-soluble quinone oxidoreductases capable of reducing quinone substrates via a concerted two-electron mechanism have been implicated in bacterial antioxidant defence. Twoelectron transfer avoids formation of dangerously reactive semi-quinone intermediates, moreover previous work in Pseudomonas putida indicated a direct protective effect for the quinols generated by an over-expressed oxidoreductase. Here, the Pseudomonas aeruginosa orthologs of five quinone oxidoreductases--MdaB, ChrR, WrbA, NfsB, and NQO1--were tested for their possible role in defending P. aeruginosa against H2O2 challenge. In in vitro assays, each enzyme was shown to reduce quinone substrates with only minimal semiquinone formation. However, when each was individually over-expressed in P. aeruginosa no overt H2O2-protective phenotype was observed. It was shown that this was due to a masking effect of the P. aeruginosa catalase, KatA; in a katA mutant, H2O2 challenged strains over-expressing the WrbA and MdaB orthologs grew significantly better than the empty plasmid control. A growth advantage was also observed for H2O2 challenged P. putida strains over-expressing P. aeruginosa wrbA, mdaB or katA. Despite not conferring a growth advantage to wild type P. aeruginosa, it is possible that these quinone oxidoreductases defend against H2O2 toxicity at lower concentrations.
authors.affiliation: School of Biological Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand.
authors.forename: Laura K
authors.initials: LK
authors.lastname: Green
authors.forename: Anne C
authors.initials: AC
authors.lastname: La Flamme
authors.forename: David F
authors.initials: DF
authors.lastname: Ackerley
mesh_terms: D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000633:toxicity; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D011808:Quinone Reductases / Q000235:genetics / Q000378:metabolism*; D011809:Quinones / Q000378:metabolism
chemical_list: D011809:Quinones; D006861:Hydrogen Peroxide; D011808:Quinone Reductases
references.citation: Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3537-9
references.pmid: 10097071
references.citation: Chem Biol. 2004 Jul;11(7):971-80
references.pmid: 15271355
references.citation: J Bacteriol. 1999 Jun;181(12):3730-42
references.pmid: 10368148
references.citation: J Bacteriol. 2007 Dec;189(24):9101-7
references.pmid: 17951395
references.citation: Curr Med Chem. 2005;12(10):1161-208
references.pmid: 15892631
references.citation: J Biochem. 1978 Jan;83(1):9-17
references.pmid: 24048
references.citation: Appl Environ Microbiol. 2004 Feb;70(2):873-82
references.pmid: 14766567
references.citation: Biochemistry. 1991 Nov 5;30(44):10647-53
references.pmid: 1657151
references.citation: Nucleic Acids Res. 2003 Mar 15;31(6):1790-5
references.pmid: 12626721
references.citation: Biochem Pharmacol. 2010 Mar 1;79(5):678-87
references.pmid: 19852945
references.citation: J Bacteriol. 2006 May;188(10):3431-2
references.pmid: 16672595
references.citation: Nature. 2000 Aug 31;406(6799):959-64
references.pmid: 10984043
references.citation: BMC Genomics. 2005 Sep 08;6:115
references.pmid: 16150148
references.citation: Am J Respir Crit Care Med. 2005 Jun 1;171(11):1209-23
references.pmid: 15695491
references.citation: BMC Microbiol. 2011 Oct 03;11:218
references.pmid: 21967163
references.citation: Microbiology (Reading). 1999 Aug;145 ( Pt 8):1817-1830
references.pmid: 10463148
references.citation: J Bacteriol. 2004 Jan;186(1):248-52
references.pmid: 14679246
references.citation: Biochem Pharmacol. 2013 Apr 15;85(8):1091-103
references.pmid: 23399641
references.citation: J Biochem. 1996 Oct;120(4):736-44
references.pmid: 8947835
references.citation: Microbiology (Reading). 2000 Apr;146 ( Pt 4):787-796
references.pmid: 10784036
references.citation: J Biol Chem. 2005 Jun 17;280(24):22590-5
references.pmid: 15840577
references.citation: Infect Immun. 2004 Mar;72(3):1391-6
references.pmid: 14977943
references.citation: Infect Immun. 2005 Jul;73(7):4399-403
references.pmid: 15972537
references.citation: Methods Enzymol. 2004;382:115-44
references.pmid: 15047100
references.citation: Arch Biochem Biophys. 1982 Jun;216(1):178-85
references.pmid: 6285828
references.citation: Free Radic Res. 2005 Nov;39(11):1173-82
references.pmid: 16298743
references.citation: Adv Exp Med Biol. 1979;121(A):53-74
references.pmid: 232820
references.citation: Science. 1988 Apr 29;240(4852):640-2
references.pmid: 2834821
references.citation: Mol Cancer. 2013 Jun 10;12:58
references.pmid: 23758947
references.citation: J Bacteriol. 2005 Apr;187(8):2565-72
references.pmid: 15805502
references.citation: Protein Sci. 2007 Oct;16(10):2301-5
references.pmid: 17893367
references.citation: EMBO J. 2000 Aug 15;19(16):4237-47
references.pmid: 10944106
references.citation: Adv Enzymol Relat Areas Mol Biol. 1992;65:97-146
references.pmid: 1570770
references.citation: Free Radic Biol Med. 1997;22(1-2):329-35
references.pmid: 8958158
references.citation: J Bacteriol. 2006 May;188(10):3498-506
references.pmid: 16672604
references.citation: Nucleic Acids Res. 2011 Jan;39(Database issue):D596-600
references.pmid: 20929876