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  • Title: [ATPase activity and K+ transport in membranes of anaerobically grown trk-mutants of Escherichia coli].
    Author: Trchunian AA, Vasilian AV.
    Journal: Biokhimiia; 1993 Jul; 58(7):1062-70. PubMed ID: 8364123.
    Abstract:
    A notable (twofold) increase in N,N'-dicyclohexylcarbodiimide (DCCD)-sensitive ATPase activity at increasing concentrations of K+ ion--from zero to 100 mM was found in isolated membranes of anaerobically grown E. coli. This was also observed during changing of Rb+ concentration (but not that of Na+, CL- or NO3-) and only in the wild precursor strain and trkG (but not in trkA, trkE, or trkH mutants). The DCCD-sensitive ATPase activity did not depend on K+ concentration in membranes of bacteria grown in the presence of NaNO3. TrkG or trkH mutants of E. coli with unc-deletions displayed a slight ATPase activity which was insensitive to DCCD. The growth of the trkG mutant, unlike other trk mutants, did not depend on K+ concentration above 0.4 mM. In this case accumulation of K+ in this mutant under positive osmotic shock was notably higher. These results suggest that K(+)-dependent DCCD-sensitive ATPase activity in membranes of anaerobically grown bacteria depends critically on the functioning of F1F0-ATPase and Trk of the K+ uptake system and may be explained by a direct relationship between these transport systems. It is also probable that the trkG gene has no functional activity in anaerobically grown bacteria.
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