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The fox Operon from Rhodobacter Strain SW2 Promotes Phototrophic Fe(II) Oxidation in Rhodobacter capsulatus SB1003

Croal, Laura R. and Jiao, Yongqin and Newman, Dianne K. (2007) The fox Operon from Rhodobacter Strain SW2 Promotes Phototrophic Fe(II) Oxidation in Rhodobacter capsulatus SB1003. Journal of Bacteriology, 189 (5). pp. 1774-1782. ISSN 0021-9193. PMCID PMC1855712.

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Anoxygenic photosynthesis based on Fe(II) is thought to be one of the most ancient forms of metabolism and is hypothesized to represent a transition step in the evolution of oxygenic photosynthesis. However, little is known about the molecular basis of this process because, until recently (Y. Jiao and D. K. Newman, J. Bacteriol. 189:1765-1773, 2007), most phototrophic Fe(II)-oxidizing bacteria have been genetically intractable. In this study, we circumvented this problem by taking a heterologous-complementation approach to identify a three-gene operon (the foxEYZ operon) from Rhodobacter sp. strain SW2 that confers enhanced light-dependent Fe(II) oxidation activity when expressed in its genetically tractable relative Rhodobacter capsulatus SB1003. The first gene in this operon, foxE, encodes a c-type cytochrome with no significant similarity to other known proteins. Expression of foxE alone confers significant light-dependent Fe(II) oxidation activity on SB1003, but maximal activity is achieved when foxE is expressed with the two downstream genes foxY and foxZ. In SW2, the foxE and foxY genes are cotranscribed in the presence of Fe(II) and/or hydrogen, with foxZ being transcribed only in the presence of Fe(II). Sequence analysis predicts that foxY encodes a protein containing the redox cofactor pyrroloquinoline quinone and that foxZ encodes a protein with a transport function. Future biochemical studies will permit the localization and function of the Fox proteins in SW2 to be determined.

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Newman, Dianne K.0000-0003-1647-1918
Additional Information:© 2007, American Society for Microbiology. Received 31 August 2006/ Accepted 12 December 2006. Published ahead of print on 22 December 2006. We thank Doug Lies, Nicky Caiazza, Lars Dietrich, and anonymous reviewers for comments on the manuscript and the members of the Newman lab for helpful discussion. This work was supported by grants from the Packard Foundation and Howard Hughes Medical Institute to D.K.N. and an NSF graduate fellowship to L.R.C.
Funding AgencyGrant Number
David and Lucile Packard FoundationUNSPECIFIED
Howard Hughes Medical Institute (HHMI)UNSPECIFIED
NSF Graduate Research FellowshipUNSPECIFIED
Issue or Number:5
PubMed Central ID:PMC1855712
Record Number:CaltechAUTHORS:CROjbact07
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7558
Deposited By: Archive Administrator
Deposited On:03 Mar 2007
Last Modified:12 Dec 2019 17:06

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