This project proposes to study the structure and activities of BJ38, a lectin purified from extracts of Bradyrhizobium japonicum. This protein binds to glycoconjugates containing lactose (Lac) or galactose (Gal). Derivatives of Gal at C-2, galactosamine and N-acetyl-D-galactosamine bound with much lower affinity. This specificity correlated with the behavior of intact Rhizobium in four carbohydrate-specific binding assays: (a) adsorption to Lac-Sepharose beads; (b) heterotypic binding to cultured soybean (SB-1) cells; (c) heterotypic adhesion to soybean roots; and (d) homotypic autoagglutination. These observations indicate the possibility that all of these binding activities were mediated by the same component(s) and the BJ38 is a key candidate for the carbohydrate-specific binding. The specific objectives of the proposed research are: [a] to demonstrate and quantitate the binding of purified BJ38 to soybean cells and to B. japonicum cells; [b] to test the possibility that soluble BJ38 bound to soybean cells will block adhesion of B. japonicum and that BJ38 bound to the bacteria will block autoagglutination; [c] to test whether univalent Fab fragments of antibodies directed against BJ38 will inhibit heterotypic binding to soybean cells and homotypic autoagglutination; [d] to analyze the expression and localization of BJ38 in B. japonicum cells; [e] to carry out molecular cloning of BJ38; [f] to determine the partial amino acid sequence of BJ38 at the protein level and to derive the complete amino acid sequence from the DNA sequence; [g] to test whether carbohydrate-specific binding can be restored in mutant B. japonicum by complementation with the BJ38 gene.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM045200-03
Application #
3304570
Study Section
Pathobiochemistry Study Section (PBC)
Project Start
1991-04-01
Project End
1994-03-31
Budget Start
1993-04-01
Budget End
1994-03-31
Support Year
3
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Michigan State University
Department
Type
Schools of Osteopathy
DUNS #
193247145
City
East Lansing
State
MI
Country
United States
Zip Code
48824