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Role of individual nap gene cluster products in NapC-independent nitrate respiration of Wolinella succinogenes.

Kern, M. and Mager, A. M. and Simon, J. (2007):
Role of individual nap gene cluster products in NapC-independent nitrate respiration of Wolinella succinogenes.
In: Microbiology (Reading, England), pp. 3739-47, 153, (Pt 11), ISSN 1350-0872,
[Article]

Abstract

Bacterial nap gene clusters, encoding periplasmic nitrate reductase (NapA), are complex and diverse, and the composition of the electron transport chain donating electrons to NapA is poorly characterized in most organisms. Exceptionally, Wolinella succinogenes transfers electrons from formate via the menaquinone pool to NapA independently of a membrane-bound c-type cytochrome of the NapC family. The role of individual ORFs of the W. succinogenes napAGHBFLD gene cluster is assessed here by characterizing in-frame gene inactivation mutants. The ability of the mutants to grow by nitrate respiration was tested and their NapA content and specific nitrate reductase activity were determined. The napB and napD gene products proved to be essential for nitrate respiration, with NapD being required for the production of mature NapA. Inactivation of either subunit of the putative membrane-bound menaquinol dehydrogenase complex NapGH almost abolished growth by nitrate respiration. Substitution of the twin-arginine sequence of NapG had the same effect as absence of NapG. Phenotypes of mutants lacking either NapF or NapL suggest that both proteins function in NapA assembly and/or export. The data substantiate the current model of the composition of the NapC-independent electron transport chain as well as of NapA maturation, and indicate the presence of an alternative electron transport pathway to NapA.

Item Type: Article
Erschienen: 2007
Creators: Kern, M. and Mager, A. M. and Simon, J.
Title: Role of individual nap gene cluster products in NapC-independent nitrate respiration of Wolinella succinogenes.
Language: English
Abstract:

Bacterial nap gene clusters, encoding periplasmic nitrate reductase (NapA), are complex and diverse, and the composition of the electron transport chain donating electrons to NapA is poorly characterized in most organisms. Exceptionally, Wolinella succinogenes transfers electrons from formate via the menaquinone pool to NapA independently of a membrane-bound c-type cytochrome of the NapC family. The role of individual ORFs of the W. succinogenes napAGHBFLD gene cluster is assessed here by characterizing in-frame gene inactivation mutants. The ability of the mutants to grow by nitrate respiration was tested and their NapA content and specific nitrate reductase activity were determined. The napB and napD gene products proved to be essential for nitrate respiration, with NapD being required for the production of mature NapA. Inactivation of either subunit of the putative membrane-bound menaquinol dehydrogenase complex NapGH almost abolished growth by nitrate respiration. Substitution of the twin-arginine sequence of NapG had the same effect as absence of NapG. Phenotypes of mutants lacking either NapF or NapL suggest that both proteins function in NapA assembly and/or export. The data substantiate the current model of the composition of the NapC-independent electron transport chain as well as of NapA maturation, and indicate the presence of an alternative electron transport pathway to NapA.

Journal or Publication Title: Microbiology (Reading, England)
Volume: 153
Number: Pt 11
Divisions: 10 Department of Biology > Microbial Energy Conversion and Biotechnology
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10 Department of Biology
Date Deposited: 16 Dec 2010 08:38
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