Laval-Favre K, Letouvet-Pawlak B, Friedrich T, Alexandre J, Guespin-Michel J F
Laboratoire de Microbiologie du Froid, URA CNRS 203, Faculté des Sciences, Université de Rouen, Aignan, France.
Mol Microbiol. 1997 Mar;23(5):1043-52. doi: 10.1046/j.1365-2958.1997.2901655.x.
The secretion of numerous proteins during vegetative growth of Myxococcus xanthus, and the multicellular development cycle induced upon starvation of these bacteria, are partially interrelated in so far as mutants impaired in extracellular protein production are unable to undergo development. We have cloned and sequenced a gene in which a Tn5 insertion leads to a decrease in the production of most, if not all, extracellular proteins, and prevents development and sporulation. The deduced protein is homologous to the putative ubiquinone-binding subunit of bacterial and mitochondrial NADH:ubiquinone oxidoreductases (complex I). This is the first example of the presence of this complex in a bacterium from subclass delta of the proteobacteria. This gene is expressed during growth and during early development. As its disruption by Tn5 does not impair growth of the mutant strain, we assume the presence of a second alternative NADH oxidoreductase, and suggest that the phenotypic alterations caused by the mutation are due to a decrease in the proton-motive force.
在黄色粘球菌营养生长期间多种蛋白质的分泌，以及这些细菌饥饿时诱导的多细胞发育周期，在一定程度上是相互关联的，因为细胞外蛋白质产生受损的突变体无法进行发育。我们克隆并测序了一个基因，其中Tn5插入导致大多数（如果不是全部）细胞外蛋白质的产生减少，并阻止发育和孢子形成。推导的蛋白质与细菌和线粒体NADH：泛醌氧化还原酶（复合体I）的假定泛醌结合亚基同源。这是在变形菌纲δ亚类细菌中存在该复合体的第一个例子。该基因在生长期间和早期发育期间表达。由于Tn5对其的破坏不损害突变菌株的生长，我们假设存在第二种替代的NADH氧化还原酶，并表明由该突变引起的表型改变是由于质子动力势的降低。
