ISSN:
1365-2958
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Medicine
Notes:
The potassium-translocating Kdp-ATPase of Escherichia coli shares common functional properties with eukaryotic P-type ATPases. The KdpB subunit has been identified as the catalytic subunit forming the phosphorylated intermediate. Substitution of Asp 307 in KdpB by Glu, Asn, Gin, Tyr, His, Ala or Ser by site-directed mutagenesis and the subsequent transfer of the point mutations to the chromosome revealed that the mutants were not functioning with respect to cell growth at low K’ concentrations and ATPase activity as well as phosphorylation capacity of the purified Kdp complex. These findings indicate that Asp-307 in KdpB is the phosphorylation site of the Kdp-ATPase. In contrast, replacement of the close but non-conserved Asp-300 by Asn or Glu has no immediate influence on the enzyme functions tested. However, the Km for K+ of the ATPase activity has been increased 30-fold compared with the wild-type enzyme.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2958.1992.tb01786.x
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