Studies of the conformational stability of invasion plasmid antigen B from Shigella

Shigella spp. are the causative agent of shigellosis, the second leading cause of diarrhea in children of ages 2–5. Despite many years of research, a protective vaccine has been elusive. We recently demonstrated that invasion plasmid antigens B and D (IpaB and IpaD) provide protection against S. fle...

Full description

Saved in:
Bibliographic Details
Published in:Protein science 2013-05, Vol.22 (5), p.666-670
Main Authors: Choudhari, Shyamal P., Kramer, Ryan, Barta, Michael L., Greenwood, Jamie C., Geisbrecht, Brian V., Joshi, Sangeeta B., Picking, William D., Middaugh, C. Russell, Picking, Wendy L.
Format: Article
Language:English
Subjects:
Antigens, Bacterial - chemistry
Antigens, Bacterial - metabolism
Bacterial Proteins - chemistry
Bacterial Proteins - metabolism
Bacteriology
Child
Circular Dichroism
Diarrhea
Dysentery, Bacillary - microbiology
empirical phase diagram
For the Record
Humans
Hydrogen-Ion Concentration
Invasions
IpaB
IpgC
Molecular Chaperones - chemistry
Molecular Chaperones - metabolism
Protein Stability
Protein Unfolding
Shigella - chemistry
Shigella - metabolism
Shigella vaccine
type III secretion system
Vaccines
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Shigella spp. are the causative agent of shigellosis, the second leading cause of diarrhea in children of ages 2–5. Despite many years of research, a protective vaccine has been elusive. We recently demonstrated that invasion plasmid antigens B and D (IpaB and IpaD) provide protection against S. flexneri and S. sonnei. These proteins, however, have very different properties which must be recognized and then managed during vaccine formulation. Herein, we employ spectroscopy to assess the stability of IpaB as well as IpgC (invasion protein gene), IpaB's cognate chaperone, and the IpaB/IpgC complex. The resulting data are mathematically summarized into a visual map illustrating the stability of the proteins and their complex as a function of pH and temperature. The IpaB/IpgC complex exhibits thermal stability at higher pH values but, though initially stable, quickly unfolds with increasing temperature when maintained at lower pH. In contrast, IpaB is a much more complex protein exhibiting increased stability at higher pH, but shows initial instability at lower pH values with pH 5 showing a distinct transition. IpgC precipitates at and below pH 5 and is stable above pH 7. Most strikingly, it is clear that complex formation results in stabilization of the two components. This work serves as a basis for the further development of IpaB as a vaccine candidate as well as extends our understanding of the structural stability of the Shigella type III secretion system.
ISSN:0961-8368
1469-896X
DOI:10.1002/pro.2249