Journal article
Structure and Sequence Conservation of hao Cluster Genes of Autotrophic Ammonia-Oxidizing Bacteria: Evidence for Their Evolutionary History
Applied and environmental microbiology, Vol.71(9), pp.5371-5382
09/2005
Handle:
https://hdl.handle.net/2376/105146
PMCID: PMC1214698
PMID: 16151127
Abstract
Comparison of the organization and sequence of the
hao
(hydroxylamine oxidoreductase) gene clusters from the gammaproteobacterial autotrophic ammonia-oxidizing bacterium (aAOB)
Nitrosococcus oceani
and the betaproteobacterial aAOB
Nitrosospira multiformis
and
Nitrosomonas europaea
revealed a highly conserved gene cluster encoding the following proteins:
hao
, hydroxylamine oxidoreductase;
orf2
, a putative protein;
cycA
, cytochrome
c
554
; and
cycB
, cytochrome
c
m
552
. The deduced protein sequences of HAO,
c
554
, and
c
m
552
were highly similar in all aAOB despite their differences in species evolution and codon usage. Phylogenetic inference revealed a broad family of multi-
c
-heme proteins, including HAO, the pentaheme nitrite reductase, and tetrathionate reductase. The
c
-hemes of this group also have a nearly identical geometry of heme orientation, which has remained conserved during divergent evolution of function. High sequence similarity is also seen within a protein family, including cytochromes
c
m
552
, NrfH/B, and NapC/NirT. It is proposed that the hydroxylamine oxidation pathway evolved from a nitrite reduction pathway involved in anaerobic respiration (denitrification) during the radiation of the
Proteobacteria
. Conservation of the hydroxylamine oxidation module was maintained by functional pressure, and the module expanded into two separate narrow taxa after a lateral gene transfer event between gamma- and betaproteobacterial ancestors of extant aAOB. HAO-encoding genes were also found in six non-aAOB, either singly or tandemly arranged with an
orf2
gene, whereas a
c
554
gene was lacking. The conservation of the
hao
gene cluster in general and the uniqueness of the
c
554
gene in particular make it a suitable target for the design of primers and probes useful for molecular ecology approaches to detect aAOB.
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Details
- Title
- Structure and Sequence Conservation of hao Cluster Genes of Autotrophic Ammonia-Oxidizing Bacteria: Evidence for Their Evolutionary History
- Creators
- David J Bergmann - Black Hills State University, Spearfish, South Dakota 57783Alan B Hooper - Black Hills State University, Spearfish, South Dakota 57783Martin G Klotz - Black Hills State University, Spearfish, South Dakota 57783
- Publication Details
- Applied and environmental microbiology, Vol.71(9), pp.5371-5382
- Academic Unit
- Molecular Biosciences, School of
- Publisher
- American Society for Microbiology
- Identifiers
- 99900546892301842
- Language
- English
- Resource Type
- Journal article