PMID:9515899
| Citation |
Zhong, X and Tai, PC (1998) When an ATPase is not an ATPase: at low temperatures the C-terminal domain of the ABC transporter CvaB is a GTPase. J. Bacteriol. 180:1347-53 |
|---|---|
| Abstract |
The ATP-binding cassette (ABC) transporters belong to a large superfamily of proteins which share a common function and a common nucleotide-binding domain. The CvaB protein from Escherichia coli is a member of the bacterial ABC exporter subfamily and is essential for the export of the peptide antibiotic colicin V. Here we report that, surprisingly, the CvaB carboxyl-terminal nucleotide-binding domain (BCTD) can be preferentially cross-linked to GTP but not to ATP at low temperatures. The cross-linking is Mg2+ and Mn2+ dependent. However, BCTD possesses similar GTPase and ATPase activities at 37 degrees C, with the same kinetic parameters and with similar responses to inhibitors. Moreover, a point mutation (D654H) in CvaB that completely abolishes colicin V secretion severely impairs both GTPase and ATPase activities in the corresponding BCTD, indicating that the two activities are from the same enzyme. Interestingly, hydrolysis activity of ATP is much more cold sensitive than that of GTP: BCTD possesses mainly GTP hydrolysis activity at 10 degrees C, consistent with the cross-linking results. These findings suggest a novel mechanism for an ABC protein-mediated transport with specificity for GTP hydrolysis. |
| Links | |
| Keywords |
ATP-Binding Cassette Transporters/genetics; ATP-Binding Cassette Transporters/metabolism; ATP-Binding Cassette Transporters/physiology; Adenosine Triphosphatases/genetics; Adenosine Triphosphatases/metabolism; Adenosine Triphosphate/metabolism; Cloning, Molecular; Colicins/genetics; Colicins/metabolism; Colicins/secretion; Escherichia coli/enzymology; Escherichia coli/genetics; Escherichia coli/metabolism; Escherichia coli Proteins; GTP Phosphohydrolases/genetics; GTP Phosphohydrolases/metabolism; Gene Expression; Glutathione Transferase/genetics; Glutathione Transferase/radiation effects; Guanosine Triphosphate/metabolism; Guanosine Triphosphate/radiation effects; Histidine/genetics; Histidine/radiation effects; Kinetics; Magnesium/metabolism; Manganese/metabolism; Plasmids; Point Mutation; Recombinant Fusion Proteins/metabolism; Recombinant Fusion Proteins/physiology; Recombination, Genetic; Ultraviolet Rays |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.