CARBOHYDRATE BINDING PROTEIN OF B. JAPONICUM

日本大戟的碳水化合物结合蛋白

• 批准号: 3304569
• 负责人: SIUCHEONG HO
• 金额: $ 12.6万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-04-01 至 1994-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3304569
• 关键词: Rhizobiaceae; agglutination reaction; agglutinins; bacterial genetics; bacterial proteins; cell adhesion; gene complementation; genetic manipulation; glycoprotein structure; immunoglobulins; laboratory rabbit; lectin; molecular cloning; mutant; nucleic acid sequence; protein purification; protein structure function; soybeans; tissue /cell culture

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.

本项目拟对BJ38， a的结构和活性进行研究