TY - JOUR
T1 - Purification and characterization of OmcZ, an outer-surface, octaheme c-type cytochrome essential for optimal current production by geobacter sulfurreducens
AU - Inoue, Kengo
AU - Qian, Xinlci
AU - Morgado, Leonor
AU - Kim, Byoung Chan
AU - Mester, Tünde
AU - Izallalen, Mounir
AU - Salgueiro, Carlos A.
AU - Lovley, Derek R.
N1 - info:eu-repo/grantAgreement/FCT/3599-PPCDT/74498/PT#
info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBD%2F37415%2F2007/PT#
Office of Science (BER), U.S. Department of Energy, Cooperative Agreement no. DE-FC02-02ER63446.
Office of Naval Research award no. N00014-10-1-0084.
Sem PDF conforme despacho.
PY - 2010/6/1
Y1 - 2010/6/1
N2 -
Previous studies have demonstrated that Geobacter sulfurreducens requires the c-type cytochrome OmcZ, which is present in large (OmcZ
L
; 50-kDa) and small (OmcZ
s
; 30-kDa) forms, for optimal current production in microbial fuel cells. This protein was further characterized to aid in understanding its role in current production. Subcellular-localization studies suggested that OmcZ
s
was the predominant extracellular form of OmcZ. N- and C-terminal amino acid sequence analysis of purified OmcZs and molecular weight measurements indicated that OmcZ
s
is a cleaved product of OmcZL retaining all 8 hemes, including 1 heme with the unusual c-type heme-binding motif CX
14
CH. The purified OmcZ
s
was remarkably thermally stable (thermaldenaturing temperature, 94.2°C). Redox titration analysis revealed that the midpoint reduction potential of OmcZ
s
is approximately - 220 mV (versus the standard hydrogen electrode [SHE]) with nonequivalent heme groups that cover a large reduction potential range (- 420 to - 60 mV). OmcZ
s
transferred electrons in vitro to a diversity of potential extracellular electron acceptors, such as Fe(III) citrate, U(VI), Cr(VI), Au(III), Mn(IV) oxide, and the humic substance analogue anthraquinone-2,6-disulfonate, but not Fe(III) oxide. The biochemical properties and extracellular localization of OmcZ suggest that it is well suited for promoting electron transfer in current-producing biofilms of G. sulfurreducens.
AB -
Previous studies have demonstrated that Geobacter sulfurreducens requires the c-type cytochrome OmcZ, which is present in large (OmcZ
L
; 50-kDa) and small (OmcZ
s
; 30-kDa) forms, for optimal current production in microbial fuel cells. This protein was further characterized to aid in understanding its role in current production. Subcellular-localization studies suggested that OmcZ
s
was the predominant extracellular form of OmcZ. N- and C-terminal amino acid sequence analysis of purified OmcZs and molecular weight measurements indicated that OmcZ
s
is a cleaved product of OmcZL retaining all 8 hemes, including 1 heme with the unusual c-type heme-binding motif CX
14
CH. The purified OmcZ
s
was remarkably thermally stable (thermaldenaturing temperature, 94.2°C). Redox titration analysis revealed that the midpoint reduction potential of OmcZ
s
is approximately - 220 mV (versus the standard hydrogen electrode [SHE]) with nonequivalent heme groups that cover a large reduction potential range (- 420 to - 60 mV). OmcZ
s
transferred electrons in vitro to a diversity of potential extracellular electron acceptors, such as Fe(III) citrate, U(VI), Cr(VI), Au(III), Mn(IV) oxide, and the humic substance analogue anthraquinone-2,6-disulfonate, but not Fe(III) oxide. The biochemical properties and extracellular localization of OmcZ suggest that it is well suited for promoting electron transfer in current-producing biofilms of G. sulfurreducens.
UR - http://www.scopus.com/inward/record.url?scp=77953637460&partnerID=8YFLogxK
U2 - 10.1128/AEM.00027-10
DO - 10.1128/AEM.00027-10
M3 - Article
C2 - 20400562
AN - SCOPUS:77953637460
SN - 0099-2240
VL - 76
SP - 3999
EP - 4007
JO - Applied and Environmental Microbiology
JF - Applied and Environmental Microbiology
IS - 12
ER -