Genetic evidence for a fourth terminal oxidase in Bradyrhizobium japonicum.
Bradyrhizobium japonicum, a symbiotic nitrogen-fixing bacterium, has a complex respiratory electron-transport chain, capable of functioning throughout a wide range of oxygen tensions. It does so by synthesizing a number of terminal oxidases, each appropriate for different environmental conditions. Several genes encoding terminal oxidases from B. japonicum have been cloned, but it is unknown what roles these individual oxidases play. In this paper, we describe the cloning and sequencing of the coxX gene encoding the large catalytic subunit for a fourth terminal oxidase from B. japonicum. The coxX gene encodes a 666-amino-acid (aa) protein (M(r) 74,527) that exhibits a high degree of homology to terminal oxidase proteins from a number of prokaryotic and eukaryotic species. This new oxidase exhibits greater homology to the Escherichia coli cytochrome o subunit I than any of the previously reported B. japonicum terminal oxidase genes.
Surpin
M A
MA
Department of Biology, Johns Hopkins University, Baltimore, MD 21218.
Moshiri
F
F
Murphy
A M
AM
Maier
R J
RJ
D000220:Adaptation, Biological; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000737:chemistry; D005798:Genes, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics*; D016133:Polymerase Chain Reaction; D015183:Restriction Mapping; D012230:Rhizobiaceae / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
D001426:Bacterial Proteins; C087499:CoxX protein, Bradyrhizobium japonicum; D010088:Oxidoreductases; C038862:cytochrome o oxidase; D003576:Electron Transport Complex IV