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Structural
and regulatory complexity of bacterial nitrate and nitrite
dissimilation
Abstract:
Over
the recent decade significant progress has been made allowing to analyse
the molecular basis of bacterial nitrate dissimilation with
accuracy unfeasible until recently. A lot of new data
concerning functioning of nitrate denitrification as well as
respiratory ammonification has been discovered. These studies have
shown that regulation of both processes is unexpectedly complex.
This review summarizes recent advances in biochemistry and
regulation of denitrification and respiratory ammonification including nitrate and nitrite transport. Description
is restricted to first stages of both processes; that is:
nitrate reduction, driven by the same enzyme, and nitrite
reduction step differentiating bacteria to denitrificatory and ammonificatory branches.
l. Introduction.
2. Terminology used to describe nitrate dissimilation. 2.l. Denitrification
sensu stricto versus
nitrate respiration. 2.2. Respiratory ammonification. 2.3. Energy
conservation coupled to
nitrate respiration. 3. Biochemistry and location of
dissimilatory nitrate reductases. 3.1. Membrane-bound nitrate reductase. 3.2. Periplasmic nitrate reductase. 4. Biochemistry
and location of
dissimilatory nitrite reductases. 5. Model bacteria
dissimilating nitrate. 5.1. Paracoccus
denitrificans. 5.2. Escherichia
coli. 5.3. Bacillus
subtilis. 6. Genetic regulation of nitrate dissimilation.
6.1. Oxygen
regulation. 6.1.1. ArcA/ArcB regulatory system of E. coli and nitrate respiration efficiency.
6.1.2. FNR regulatory factors. 6.2. Nitrate and nitrite
regulation in E. coli. 7. Nitrate
and nitrite transport.
7.1. Mechanism of nitrate transport. 7.2. Mechanism of nitrite
transport |
