The Mechanism of Biotin Biosynthesis

生物素生物合成机制

• 批准号: 6517935
• 负责人: MICHELE M COSPER
• 金额: $ 4.42万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6517935
• 关键词: Mossbauer spectrometry; S adenosylmethionine; biochemistry; biophysics; biotin; chemical cleavage; circular magnetic dichroism; electron spin resonance spectroscopy; free radical oxygen; iron sulfur protein; mass spectrometry; metalloproteins; molecular biology; oxidation reduction reaction; protein purification; protein structure function; vitamin biosynthesis

DESCRIPTION: (provided by applicant) Biotin (vitamin H) participates in cellular metabolism as the prosthetic group of carboxylases, decarboxylases, and transcarboxylases. The final step of biotin biosynthesis involves the insertion of sulfur into dithiobiotin, a chemically challenging reaction that entails the formation C-S bonds at inactivated, saturated carbon atoms. This transformation is dependent upon the bioB gene product, biotin synthase. Biotin synthase is an iron-sulfur (Fe-S) protein and belongs to the family of S-adenosylmethionine-dependent radical-generating Fe-S enzymes. New roles for Fe-S clusters are beginning to emerge in the generation of radical intermediates and in the donation of sulfur in the final step of biotin synthesis. Although the exact role of the Fe-S cluster is not fully understood, the use of the Fe-cluster as a sulfur donor in biotin biosynthesis implies novel S-based Fe-S cluster chemistry. Similar sulfur-based chemistry could be involved in the cleavage of S-adenosylmethionine to generate the 5?-deoxyadenosyl radical. The major objectives of this research proposal are to use molecular biology and biochemical methodologies together with the application of biophysical spectroscopic techniques (EPR, absorption/Cd/MCD, resonance Raman, and Mossbauer spectroscopies and mass spectrometry) to determine the mechanism of Fe-S cluster-mediated reductive cleavage of S-adenosylmethionine, the nature of the cluster transformation that occurs upon donation of the sulfur atom for biotin biosynthesis, and the requirements for catalytic biosynthesis of biotin.

描述：（由申请人提供）生物素（维生素H）参与 作为羧化酶，脱羧酶， 和转羧酶。生物素生物合成的最后一步涉及 将硫插入二硫代生物锡中，这是一种具有化学挑战性的反应， 需要在失活的饱和碳原子处形成C-S键。这 转化依赖于bioB基因产物生物素合酶。生物素 合成酶是铁-硫（Fe-S）蛋白，并且属于铁-硫（Fe-S）蛋白家族。 S-腺苷甲硫氨酸依赖性自由基生成Fe-S酶。的新的作用 Fe-S团簇开始出现在自由基的生成过程中， 在生物素的最后一步中， 合成.虽然Fe-S簇的确切作用尚未完全了解， 在生物素生物合成中使用Fe簇作为硫供体意味着 新型硫基Fe-S簇化学。类似的硫基化学可能是 参与S-腺苷甲硫氨酸的切割以产生 五个？脱氧腺苷自由基本研究计划的主要目的是 使用分子生物学和生物化学方法， 应用生物物理光谱技术（EPR，吸收/Cd/MCD， 共振拉曼和穆斯堡尔光谱和质谱）， 确定了Fe-S团簇介导的还原裂解机理， S-腺苷甲硫氨酸，发生在 生物素生物合成的硫原子的捐赠，以及 生物素的催化生物合成。