Strain O139 of Vibrio cholerae, identified as a cause of epidemic cholera in Asia, is encapsulated, which raises serious public health concerns. This pathogen is antigenically distinct from O1 strains. The applicant has reported on the covalent chemical structure of the polysaccharide capsule and has initiated studies on the polysaccharide as a vaccine component. A working hypothesis concerning the polysaccharide is that based on analogy to similar epitopes found in Lewis blood group oligosaccharides, four of the six sugar residues in the repeating subunit, adopt a well defined fixed conformation with the linkages to the other two residues forming a flexible hinge. Tests of this idea will involve computer molecular modeling and NMR measurements involving isotope enrichment in 13C and 15N to facilitate approach to structural and dynamics issues. Long range carbon coupling constants, 3JHC and 3JCC, will be measured and correlated with glycosidic dihedral angles. Three-dimensional heteronuclear NMR spectroscopy will provide enhanced spectral resolution in NOESY experiments. Polysaccharide dynamics will be investigated by indirectly measured heteronuclear 13C and 15N relaxation rates, which will be interpreted using spectral density mapping methods as well as several forms of the model-free treatment augmented to include anisotropic tumbling and slower exchange processes. Oligosaccharide fragments will test the hypothesis of a conformational epitope that depends on molecular size. The oligosaccharides are to be used in development of chemically modified protein conjugates for vaccine development.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM057211-01A1
Application #
2761332
Study Section
Biophysical Chemistry Study Section (BBCB)
Project Start
1999-01-01
Project End
2001-12-31
Budget Start
1999-01-01
Budget End
1999-12-31
Support Year
1
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Maryland Balt CO Campus
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
City
Baltimore
State
MD
Country
United States
Zip Code
21250
Adeyeye, Jacob; Azurmendi, Hugo F; Stroop, Corne' J M et al. (2003) Conformation of the hexasaccharide repeating subunit from the Vibrio cholerae O139 capsular polysaccharide. Biochemistry 42:3979-88
Azurmendi, Hugo F; Bush, C Allen (2002) Tracking alignment from the moment of inertia tensor (TRAMITE) of biomolecules in neutral dilute liquid crystal solutions. J Am Chem Soc 124:2426-7
Stroop, Corne J M; Bush, C Allen; Marple, Ronita L et al. (2002) Carbohydrate analysis of bacterial polysaccharides by high-pH anion-exchange chromatography and online polarimetric determination of absolute configuration. Anal Biochem 303:176-85
Stroop, Corne J M; Xu, Qiuwei; Retzlaff, Mary et al. (2002) Structural analysis and chemical depolymerization of the capsular polysaccharide of Streptococcus pneumoniae type 1. Carbohydr Res 337:335-44
Azurmendi, Hugo F; Bush, C Allen (2002) Conformational studies of blood group A and blood group B oligosaccharides using NMR residual dipolar couplings. Carbohydr Res 337:905-15
Azurmendi, Hugo F; Martin-Pastor, Manuel; Bush, C Allen (2002) Conformational studies of Lewis X and Lewis A trisaccharides using NMR residual dipolar couplings. Biopolymers 63:89-98
Gunawardena, S; Fiore, C R; Johnson, J A et al. (1999) Conformation of a rigid tetrasaccharide epitope in the capsular polysaccharide of Vibrio cholerae O139. Biochemistry 38:12062-71