A membrane-bound nitrate reductase encoded by the narGHJI operon is responsible for anaerobic respiration in Halomonas maura
- Resource Type
- Authors
- Ana del Moral; Inmaculada Llamas; Montserrat Argandoña; Fernando Martínez-Checa; Yolanda Arco; Emilia Quesada
- Source
- Extremophiles. 10:411-419
- Subject
- DNA, Bacterial
Anaerobic respiration
Operon
Molecular Sequence Data
Reductase
Biology
Nitrate reductase
Nitrate Reductase
Microbiology
Insertional mutagenesis
chemistry.chemical_compound
Nitrate
Gene cluster
Anaerobiosis
DNA Primers
Halomonas
Membranes
Base Sequence
Chromosome Mapping
General Medicine
biology.organism_classification
chemistry
Biochemistry
Genes, Bacterial
Molecular Medicine
Plasmids
- Language
- ISSN
- 1433-4909
1431-0651
The halophilic bacterium Halomonas maura is capable of anaerobic respiration on nitrates. By insertional mutagenesis with the minitransposon Tn-5 we obtained the mutant Tc62, which was incapable of anaerobic respiration on nitrates. An analysis of the regions adjacent to the transposon allowed us to characterize the membrane-bound anaerobic-respiratory nitrate reductase narGHJI gene cluster in H. maura. We identified consensus sequences for fumarate and nitrate reductase regulator (FNR)-like protein-binding sites in the promoter regions of the nar genes and consensus sequences corresponding to the NarL binding sites upstream of the nar genes. RT-PCR analysis showed that the narGHJI operon was expressed in response to anaerobic conditions when nitrate was available as electron acceptor. This membrane-bound nitrate reductase is the only enzyme responsible for anaerobic respiration on nitrate in H. maura. In this article we discuss the possible relationship between this enzyme and a dissimilatory nitrate-reduction-to-ammonia process (DNRA) in H. maura and its role in the colonization of the rhizosphere.