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Title: Identification and Characterization of UndA-HRCR-6, an Outer Membrane Endecaheme c-Type Cytochrome of Shewanella sp. Strain HRCR-6

Abstract

The outer membrane decaheme c-type cytochromes (c-Cyt) MtrC and OmcA of Shewanella oneidensis MR-1(MR-1) play critical roles in extracellular reduction of iron [Fe(III)] oxides and uranium [ U(VI)]. To identify and characterize the outer membrane c-Cyts found in the metal-reducing Shewanella strains isolated from the Hanford Reach of the Columbia River (HRCR), 7 HRCR isolates were tested for the presence of mtrC, omcA and undA1 (a gene encoding a putative 11-heme c-Cyt) homologues in their genomes. All 7 tested strains possessed an mtrC homologue, while 3 strains had an omcA homologue and the remaining 4 strains contained an undA1 homologue. The coding region of an undA1 homologue from HRCR isolate 6 was cloned and sequenced. Because it was 93% identical to the UndA of S. baltica OS223, the protein product encoded by this sequenced gene was named as UndA-HRCR6. In MR-1, UndA-HRCR6 (i) restored an MR-1 mutant’s ability to reduce solid phase ferrihydrite at 40% of that for MR-1 wild type, (ii) increased extracellular formation of UO2 associated with the outer membrane and extracellular polymeric substances in a U(VI) reduction assay and (iii) was secreted to the extracellular environment by bacterial type II secretion system. UndA-HRCR6 was purified from themore » membrane fraction following its overexpression in MR-1 cells. Purified UndA-HRCR6 possessed 11 heme-Fe and reduced ferric complexes. Collectively, these results show that UndA-HRCR6 is an outer membrane endecaheme c-Cyt and can serve an extracellular metal reductase with functions similar to that of MR-1 MtrC and OmcA.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1023724
Report Number(s):
PNNL-SA-77918
Journal ID: ISSN 0099-2240; AEMIDF; 13994; KP1702030; TRN: US201120%%1060
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Applied and Environmental Microbiology, 77(15):5521-5523
Additional Journal Information:
Journal Volume: 77; Journal Issue: 15; Journal ID: ISSN 0099-2240
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 54 ENVIRONMENTAL SCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; BACTERIA; COLUMBIA RIVER; COMPLEXES; CYTOCHROMES; FUNCTIONS; GENES; IRON OXIDES; MEMBRANES; METALS; OXIDOREDUCTASES; PROTEINS; REDUCTION; SECRETION; SOLIDS; URANIUM; Environmental Molecular Sciences Laboratory

Citation Formats

Shi, Liang, Belchik, Sara M., Wang, Zheming, Kennedy, David W., Dohnalkova, Alice, Marshall, Matthew J., Zachara, John M., and Fredrickson, Jim K. Identification and Characterization of UndA-HRCR-6, an Outer Membrane Endecaheme c-Type Cytochrome of Shewanella sp. Strain HRCR-6. United States: N. p., 2011. Web. doi:10.1128/AEM.00614-11.
Shi, Liang, Belchik, Sara M., Wang, Zheming, Kennedy, David W., Dohnalkova, Alice, Marshall, Matthew J., Zachara, John M., & Fredrickson, Jim K. Identification and Characterization of UndA-HRCR-6, an Outer Membrane Endecaheme c-Type Cytochrome of Shewanella sp. Strain HRCR-6. United States. doi:10.1128/AEM.00614-11.
Shi, Liang, Belchik, Sara M., Wang, Zheming, Kennedy, David W., Dohnalkova, Alice, Marshall, Matthew J., Zachara, John M., and Fredrickson, Jim K. Mon . "Identification and Characterization of UndA-HRCR-6, an Outer Membrane Endecaheme c-Type Cytochrome of Shewanella sp. Strain HRCR-6". United States. doi:10.1128/AEM.00614-11.
@article{osti_1023724,
title = {Identification and Characterization of UndA-HRCR-6, an Outer Membrane Endecaheme c-Type Cytochrome of Shewanella sp. Strain HRCR-6},
author = {Shi, Liang and Belchik, Sara M. and Wang, Zheming and Kennedy, David W. and Dohnalkova, Alice and Marshall, Matthew J. and Zachara, John M. and Fredrickson, Jim K.},
abstractNote = {The outer membrane decaheme c-type cytochromes (c-Cyt) MtrC and OmcA of Shewanella oneidensis MR-1(MR-1) play critical roles in extracellular reduction of iron [Fe(III)] oxides and uranium [ U(VI)]. To identify and characterize the outer membrane c-Cyts found in the metal-reducing Shewanella strains isolated from the Hanford Reach of the Columbia River (HRCR), 7 HRCR isolates were tested for the presence of mtrC, omcA and undA1 (a gene encoding a putative 11-heme c-Cyt) homologues in their genomes. All 7 tested strains possessed an mtrC homologue, while 3 strains had an omcA homologue and the remaining 4 strains contained an undA1 homologue. The coding region of an undA1 homologue from HRCR isolate 6 was cloned and sequenced. Because it was 93% identical to the UndA of S. baltica OS223, the protein product encoded by this sequenced gene was named as UndA-HRCR6. In MR-1, UndA-HRCR6 (i) restored an MR-1 mutant’s ability to reduce solid phase ferrihydrite at 40% of that for MR-1 wild type, (ii) increased extracellular formation of UO2 associated with the outer membrane and extracellular polymeric substances in a U(VI) reduction assay and (iii) was secreted to the extracellular environment by bacterial type II secretion system. UndA-HRCR6 was purified from the membrane fraction following its overexpression in MR-1 cells. Purified UndA-HRCR6 possessed 11 heme-Fe and reduced ferric complexes. Collectively, these results show that UndA-HRCR6 is an outer membrane endecaheme c-Cyt and can serve an extracellular metal reductase with functions similar to that of MR-1 MtrC and OmcA.},
doi = {10.1128/AEM.00614-11},
journal = {Applied and Environmental Microbiology, 77(15):5521-5523},
issn = {0099-2240},
number = 15,
volume = 77,
place = {United States},
year = {2011},
month = {8}
}