SUBSTRATE RECOGNITION IN MULTIDRUG RESISTANCE

多重耐药性中的底物识别

• 批准号: 3198614
• 负责人: BARRY P. ROSEN
• 金额: $ 12.75万
• 依托单位: WAYNE 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: 1991-05-01 至 1994-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3198614
• 关键词: Escherichia coli; P glycoprotein; X ray crystallography; adenosinetriphosphatase; anions; antimony; arsenic; binding proteins; crosslink; detoxification; enzyme substrate; fluorescence; gene expression; genetic manipulation; ion transport; membrane proteins; molecular cloning; multidrug resistance; mutant; neoplasm /cancer chemotherapy; nucleic acid sequence; operon; point mutation; structural genes

A bacterial anion-translocating ATPase has been identified as the product of the arsenical resistance (ars) operon of resistance plasmid R773. When expressed in Escherichia coli the ATP-driven pump catalyzes extrusion of the oxyanions arsenite, antimonite, and arsenate, thus providing resistance to the toxic compounds. Although both arsenite and arsenate contain arsenic, they are chemically distinct compounds with quite different properties. This ars operon encodes an anion-translocating ATPase. The genes have cloned and sequenced, and the protein components purified. Two of the structural genes, the arsA and arsB genes, encode the two subunits of the pump. This two-component inner membrane complex binds and transports arsenite and antimonite, oxyanions with the +III oxidation state of arsenic or antimony. This complex neither transports nor provides resistance to arsenate, the oxyanion of the +V oxidation state of arsenic. The third structural gene encodes a 16 kDa polypeptide, the ArsC protein, which alters the substrate specificity of the pump to allow for recognition and transport of the alternate substrate arsenate. The failure of drug treatment in cancer chemotherapy is related to the appearance of multidrug resistance tumors. The mdr gene is the genetic locus related to multidrug resistance. The gene encodes the P- glycoprotein, an ATP-coupled resistance pump which catalyzes extrusion of cytotoxic drugs from the cells, a process analogous to that catalyzes P- glycoprotein recognizes and transports chemically distinct drugs is unknown. The overall goal of this project is elucidation of the molecular mechanism of recognition of multiple substrates by an ATP-coupled resistance pump.

细菌阴离子 - 转移ATPase已被确定为产品 抗性质粒R773的砷耐药性（ARS）操纵子。 什么时候 在大肠杆菌中表达的ATP驱动泵催化了 氧化砷，抗肌和砷酸盐，从而提供抗性 到有毒化合物。 尽管砷和砷酸盐都含有砷，但它们是化学上的 具有完全不同特性的不同化合物。 这是ARS操纵子 编码一个阴离子 - 转移ATPase。 这些基因已克隆， 测序，蛋白质成分纯化。 两个结构 基因，ARSA和ARSB基因编码泵的两个亚基。 这 两个组件内膜复合物结合并运输砷和 抗肌，氧化氧化态或锑的氧化状态。 这种复合物既不运输也不提供对砷的抵抗力， 砷氧化态的氧气。 第三结构基因 编码16 kDa多肽，即ARSC蛋白，该蛋白改变底物 泵的特异性允许识别和运输 替代底物砷。 癌症化疗中药物治疗的失败与 多药耐药性肿瘤的出现。 MDR基因是遗传 与多药电阻有关的基因座。 该基因编码p- 糖蛋白，一种ATP耦合抗性泵，可催化挤出 细胞的细胞毒性药物，类似于催化P-的过程 糖蛋白识别并运输化学上不同的药物是 未知。 该项目的总体目标是阐明分子 通过ATP耦合识别多个底物的机制 电阻泵。