抄録
An Escherichia coli mutant lacking three major K+ uptake systems, Trk, Kup, and Kdp, did not grow under low K+and high Na+ concentrations. The introduction of fkuA and of fkuB of a marine bacterium, Vibrio alginolyticus, has been reported to compensate for the growth defect by accelerating the rate of K+ uptake (Nakamura, Katoh, Shimizu, Matsuba, and Unemoto, Biochim. Biophys. Acta, 1277, 201–208 (1996)). We investigated the function of unknown genes of E. coli, yggS and yggT, homologs of fkuA and fkuB respectively. E. coli TK2420 cells, which lack the three K+ uptake systems, did not grow under high Na+ or mannitol concentrations. The growth defect was compensated by the introduction of the yggT gene alone: yggS was not required. Here we found that YggT endowed E. coli cells with a tolerance for osmotic shock, and discuss a possible mechanism.
