Disruption of <i>sucA</i> , Which Encodes the E1 Subunit of α-Ketoglutarate Dehydrogenase, Affects the Survival of <i>Nitrosomonas europaea</i> in Stationary Phase

Abstract

Although Nitrosomonas europaea lacks measurable alpha-ketoglutarate dehydrogenase activity, the recent completion of the genome sequence revealed the presence of the genes encoding the enzyme. A knockout mutation was created in the sucA gene encoding the E1 subunit. Compared to wild-type cells, the mutant strain showed an accelerated loss of ammonia monooxygenase and hydroxylamine oxidoreductase activities upon entering stationary phase. In addition, unlike wild-type cells, the mutant strain showed a marked lag in the ability to resume growth in response to pH adjustments in late stationary phase.