In:
Journal of Bacteriology, American Society for Microbiology, Vol. 180, No. 6 ( 1998-03-15), p. 1347-1353
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 Mg 2+ and Mn 2+ dependent. However, BCTD possesses similar GTPase and ATPase activities at 37°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°C, consistent with the cross-linking results. These findings suggest a novel mechanism for an ABC protein-mediated transport with specificity for GTP hydrolysis.
Type of Medium:
Online Resource
ISSN:
0021-9193
,
1098-5530
DOI:
10.1128/JB.180.6.1347-1353.1998
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
1998
detail.hit.zdb_id:
1481988-0
SSG:
12
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