Biology Reference
In-Depth Information
Table 4.
(Continued)
VIMSS id
Ortholog
Size, aas
583686
ferredoxin, subunit of nitrite reductase
122
583691
DraT
328
583692
NifH nitrogenase iron protein (EC 1.18.6. 1)
296
583693
NifD nitrogenase molybdenum-iron protein alpha chain (EC 1.18.6.1)
490
583694
NifK nitrogenase molybdenum-iron protein beta chain (EC 1. 18.6.1)
522
583695/
3337559
NifT
80
3337558
ferredoxin
63
583696
NafY -2 nitrogenase accessory factor Y
243
583710/
3337556
NifW nitrogen fi xation protein
113
3337555
NifZ
151
583711/
3337554
NifM
271
Nitric Oxide (NO) Reductase
The chromosomal region around
D. aromatica's
two
nos
Z homologs is notably dif-
ferent from near-neighbors
A. aromaticum
EbN1 and
Ralstonia solanacearum
which
encode a
nos
RZDFYL cluster.
Dechloromonas aromatica's
nos
RZDFYL operon lacks
the
nos
RFYL genes, and displays other notable differences with most nitrate reduc-
ing microbes. In
D. aromatica
, two identical
nos
Z reductase-like genes (annotated as
nos
Z1 and
nos
Z2, VIMSS583543 and VIMSS583547) are adjacent to two cytochrome
c553s, a ferredoxin, and a transport accessory protein, and are uniquely embedded
within a histidine kinase/response regulator cluster and include
nos
D and a
nap
GH-
like pair that potentially couples quinone oxidation to cytochrome c reduction. This
indicates the NO response might be involved in cell signaling and as a possible general
detoxification mechanism for NO.
The Epsilonproteobacteria
Wolinella succinogenes
is quite similar to
D.
aromatica
for NO reductase genes (both have two
nos
Z genes, a
nos
D gene and a
nap-
GH pair in the same order and orientation [83]), but the
W. succinogenes
genome
lacks the embedded signaling protein cluster. Further, NO reductase homologs Nor-
DQEBC (VIMSS582097, 582100-582103), along with the cytochrome c' protein
(VIMSS582015), which has been shown to bind NO prior to its reduction [79], are all
present, and potentially act in detoxifi cation roles. It has been shown that formation
of anaerobic biofi lms of
P. aeruginosa
(which cause chronic lung infections in cystic
fi brosis) require NO reductase when quorum has been reached [84], so a role in signal-
ing and complex cell behavior is possible.
Wolinella
succinogenes
shares other genome features with
D. aromatica
. It en-
codes only 2,042 orfs, yet has a large number of signaling proteins, histidine kinases,
and GGDEF proteins relative to its genome size. It also encodes
nif
genes, several
genes similar to virulence factors, and similarity in the NO enzyme cluster noted
above.
Wolinella
succinogenes
is evolutionarily related to two pathogenic species
