The Binding of the Cholera Toxin to the Periplasmic Vestibule of the Type II Secretion Channel
Sponsor
This research is supported by the National Institutes of Health grant AI34501
Published In
Channels
Document Type
Article
Publication Date
5-2011
Subjects
Secretin, Cryomicroscopy, Bacterial proteins, Cholera toxin
Abstract
The type II secretion system (T2SS) is a large macromolecular complex spanning the inner and outer membranes of many Gram-negative bacteria. The T2SS is responsible for the secretion of virulence factors such as cholera toxin (CT) and heat-labile enterotoxin (LT) from Vibrio cholerae and enterotoxigenic Escherichia coli, respectively. CT and LT are closely related AB5heterohexamers, composed of one A subunit and a B-pentamer. Both CT and LT are translocated, as folded protein complexes, from the periplasm across the outer membrane through the type II secretion channel, the secretin GspD. We recently published the 19 Å structure of the V. cholerae secretin (VcGspD) in its closed state and showed by SPR measurements that the periplasmic domain of GspD interacts with the B-pentamer complex. Here we extend these studies by characterizing the binding of the cholera toxin B-pentamer to VcGspD using electron microscopy of negatively stained preparations. Our studies indicate that the pentamer is captured within the large periplasmic vestibule of VcGspD. These new results agree well with our previously published studies and are in accord with a piston-driven type II secretion mechanism.
DOI
10.4161/chan.5.3.15268
Persistent Identifier
http://archives.pdx.edu/ds/psu/21416
Citation Details
Reichow, S. L., Korotkov, K. V., Gonen, M., Sun, J., Delarosa, J. R., Hol, W. G., & Gonen, T. (2011). The binding of cholera toxin to the periplasmic vestibule of the type II secretion channel. Channels, 5(3), 215-218.
Description
Appeared in Channels, published by Taylor & Francis, vol. 5, no. 3, pages 215-218. Available at https://dx.doi.org/10.4161/chan.5.3.15268
Note: At the time of writing, Steve Reichow was affiliated with the Howard Hughes Medical Institute.