title: Characterization of Shewanella oneidensis MtrC: a cell-surface decaheme cytochrome involved in respiratory electron transport to extracellular electron acceptors.
abstract: MtrC is a decaheme c-type cytochrome associated with the outer cell membrane of Fe(III)-respiring species of the Shewanella genus. It is proposed to play a role in anaerobic respiration by mediating electron transfer to extracellular mineral oxides that can serve as terminal electron acceptors. The present work presents the first spectropotentiometric and voltammetric characterization of MtrC, using protein purified from Shewanella oneidensis MR-1. Potentiometric titrations, monitored by UV-vis absorption and electron paramagnetic resonance (EPR) spectroscopy, reveal that the hemes within MtrC titrate over a broad potential range spanning between approximately +100 and approximately -500 mV (vs. the standard hydrogen electrode). Across this potential window the UV-vis absorption spectra are characteristic of low-spin c-type hemes and the EPR spectra reveal broad, complex features that suggest the presence of magnetically spin-coupled low-spin c-hemes. Non-catalytic protein film voltammetry of MtrC demonstrates reversible electrochemistry over a potential window similar to that disclosed spectroscopically. The voltammetry also allows definition of kinetic properties of MtrC in direct electron exchange with a solid electrode surface and during reduction of a model Fe(III) substrate. Taken together, the data provide quantitative information on the potential domain in which MtrC can operate.
authors: Centre for Metalloprotein Spectroscopy and Biology, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
authors: Robert S
authors: RS
authors: Hartshorne
authors: Brian N
authors: BN
authors: Jepson
authors: Tom A
authors: TA
authors: Clarke
authors: Sarah J
authors: SJ
authors: Field
authors: Jim
authors: J
authors: Fredrickson
authors: John
authors: J
authors: Zachara
authors: Liang
authors: L
authors: Shi
authors: Julea N
authors: JN
authors: Butt
authors: David J
authors: DJ
authors: Richardson
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry*; D003574:Cytochrome c Group / Q000737:chemistry* / Q000302:isolation & purification; D003580:Cytochromes / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport; D006418:Heme / Q000737:chemistry*; D011199:Potentiometry; D012119:Respiration; D020592:Shewanella / Q000737:chemistry*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D003574:Cytochrome c Group; D003580:Cytochromes; D006418:Heme; C433527:MtrC protein, Shewanella
references: J Biol Chem. 2000 Mar 24;275(12):8515-22
references: 10722689
references: J Bacteriol. 1997 Feb;179(4):1143-52
references: 9023196
references: Antonie Van Leeuwenhoek. 2002 Aug;81(1-4):215-22
references: 12448720
references: Microbiology. 2000 Mar;146 ( Pt 3):551-71
references: 10746759
references: Chemistry. 2005 Mar 18;11(7):2207-19
references: 15719360
references: Lett Appl Microbiol. 2004;39(5):466-70
references: 15482439
references: Biochem J. 2000 Jul 1;349(Pt 1):153-8
references: 10861223
references: J Biol Chem. 1995 Oct 13;270(41):24604-8
references: 7592681
references: J Biol Chem. 2003 Jul 25;278(30):27758-65
references: 12732647
references: Biochemistry. 2002 Mar 5;41(9):2921-31
references: 11863430
references: Int J Syst Bacteriol. 1999 Apr;49 Pt 2:705-24
references: 10319494
references: J Bacteriol. 1992 Jun;174(11):3429-38
references: 1592800
references: J Bacteriol. 1998 Dec;180(23):6292-7
references: 9829939
references: Appl Environ Microbiol. 2001 Jul;67(7):3236-44
references: 11425747
references: J Appl Bacteriol. 1994 Mar;76(3):253-8
references: 8157545
references: Biotechniques. 2005 Feb;38(2):297-9
references: 15727136
references: J Biol Chem. 2004 Oct 1;279(40):41333-9
references: 15280383
references: Methods Enzymol. 1978;54:411-35
references: 732578
references: J Bacteriol. 2006 Jul;188(13):4705-14
references: 16788180
references: Anal Chem. 1998 Dec 1;70(23):5062-71
references: 9852788
references: Biochemistry. 2005 Feb 15;44(6):1856-63
references: 15697211
references: J Biol Chem. 2002 Sep 20;277(38):35703-11
references: 12080059
references: Annu Rev Microbiol. 1994;48:311-43
references: 7826009
references: Biochemistry. 2003 Aug 12;42(31):9491-7
references: 12899636
references: Mol Microbiol. 2001 Feb;39(3):722-30
references: 11169112
references: Biochemistry. 2001 Sep 25;40(38):11294-307
references: 11560477
references: FEBS Lett. 2007 Jan 23;581(2):284-8
references: 17207484
references: Biophys J. 1997 Jan;72(1):435-44
references: 8994630
references: Lett Appl Microbiol. 2003;37(3):254-8
references: 12904229
references: Appl Environ Microbiol. 2002 Jun;68(6):2781-93
references: 12039733
references: J Am Chem Soc. 2001 Apr 4;123(13):2997-3005
references: 11457010
references: Biochem J. 1999 Sep 1;342 ( Pt 2):439-48
references: 10455032
references: Nat Biotechnol. 2002 Nov;20(11):1118-23
references: 12368813
references: Appl Environ Microbiol. 2001 Jan;67(1):260-9
references: 11133454
references: Anal Biochem. 1987 Feb 15;161(1):1-15
references: 3578775