Doctoral Training/Biochemistry/Transsulfuration Enzymes

博士培训/生物化学/转硫酶

• 批准号: 6935820
• 负责人: ANDRE O HUDSON
• 金额: $ 3.35万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6935820
• 关键词: Arabidopsis; aminoacid metabolism; biochemistry; carbon oxygen lyase; carbon sulfur lyase; catalyst; chemical kinetics; enzyme activity; enzyme mechanism; gene complementation; gene mutation; genetic models; molecular cloning; phenotype; predoctoral investigator; protein purification; sulfur aminoacid

DESCRIPTION (provided by applicant): The broad, long-term objective of the project is to understand the structure and function relationship of enzymes that catalyze reactions around cystathione, a central intermediate in the trans-sulfuration pathways that inter-convert cysteine and homocysteine. The trans-sulfuration enzymes play important roles in supplying cysteine and methionine for growth and in regulating the homeostasis of these amino acids. Certain genetic diseases in humans, such as homocysteinemia, are caused by mutations in the genes for these enzymes.The specific aim of project is to characterize the enzymatic function and physiological role of a gene encoded by locus At1g33320 of the genetic model plant Arabidopsis thaliana. Based on sequence homology this gene was proposed to encode cystathionine gamma-synthase, a carbon-oxygen lyase. However, preliminary evidence suggests that it functions as cystathionine beta-lyase, a carbon-sulfur tyase. This hypothesis will be examined by carrying out in vitro enzyme kinetic experiments, and by examining the function of the enzyme under in vivo conditions using a genetic complementation test. The physiological role of the gene product will also be explored by studying its expression, its subcellular localization, and by examining the phenotype resulting from knock-out mutation of the gene.

描述（由申请人提供）：该项目的广泛、长期目标是了解催化胱硫醚周围反应的酶的结构和功能关系，胱硫醚是半胱氨酸和同型半胱氨酸相互转化的反式硫化途径的中心中间体。反式硫酸化酶在提供生长所需的半胱氨酸和甲硫氨酸以及调节这些氨基酸的稳态方面发挥着重要作用。 人类的某些遗传疾病，例如同型半胱氨酸血症，是由这些酶的基因突变引起的。该项目的具体目的是表征遗传模型植物拟南芥At1g33320基因座编码的基因的酶功能和生理作用。基于序列同源性，该基因被认为编码胱硫醚γ-合酶，一种碳氧裂解酶。然而，初步证据表明它的功能与胱硫醚β-裂解酶（一种碳硫裂解酶）一样。该假设将通过进行体外酶动力学实验以及使用遗传互补测试在体内条件下检查酶的功能来检验。还将通过研究基因产物的表达、亚细胞定位以及检查基因敲除突变产生的表型来探索基因产物的生理作用。