A GENE INVOLVED IN BOTH PROTEIN SECRETION DURING GROWTH AND STARVATION-INDUCED DEVELOPMENT ENCODES A SUBUNIT OF THE NADH-UBIQUINONE OXIDOREDUCTASE IN MYXOCOCCUS-XANTHUS
K. Lavalfavre et al., A GENE INVOLVED IN BOTH PROTEIN SECRETION DURING GROWTH AND STARVATION-INDUCED DEVELOPMENT ENCODES A SUBUNIT OF THE NADH-UBIQUINONE OXIDOREDUCTASE IN MYXOCOCCUS-XANTHUS, Molecular microbiology, 23(5), 1997, pp. 1043-1052
The secretion of numerous proteins during vegetative growth of Myxococ
cus xanthus, and the multicellular development cycle induced upon star
vation of these bacteria, are partially interrelated in so far as muta
nts impaired in extracellular protein production are unable to undergo
development. We have cloned and sequenced a gene in which a Tn5 inser
tion leads to a decrease in the production of most, if not all, extrac
ellular proteins, and prevents development and sporulation. The deduce
d 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 bact
erium from subclass delta of the proteobacteria. This gene is expresse
d during growth and during early development. As its disruption by Tn5
does not impair growth of the mutant strain, we assume the presence o
f a second alternative NADH oxidoreductase, and suggest that the pheno
typic alterations caused by the mutation are due to a decrease in the
proton-motive force.