THE PHOSPHORYLATION SITE OF THE KDP-ATPASE OF ESCHERICHIA-COLI - SITE-DIRECTED MUTAGENESIS OF THE ASPARTIC-ACID RESIDUES 300 AND 307 OF THE KDPB SUBUNIT
Autor(en): | PUPPE, W SIEBERS, A ALTENDORF, K |
Stichwörter: | Biochemistry & Molecular Biology; COMPLEMENTARY-DNA; CONSERVED DOMAINS; ENVIRONMENTAL STIMULI; ION; K+-TRANSPORT; Microbiology; POTASSIUM-TRANSPORT LOCI; PROTEIN; SARCOPLASMIC-RETICULUM; SEQUENCE; TRANSLOCATING ATPASE | Erscheinungsdatum: | 1992 | Herausgeber: | WILEY-BLACKWELL | Enthalten in: | MOLECULAR MICROBIOLOGY | Band: | 6 | Ausgabe: | 23 | Startseite: | 3511 | Seitenende: | 3520 | Zusammenfassung: | 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, Gln, 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 K(m) for K+ of the ATPase activity has been increased 30-fold compared with the wild-type enzyme. |
ISSN: | 0950382X | DOI: | 10.1111/j.1365-2958.1992.tb01786.x |
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geprüft am 06.06.2024