Specificity/Regulation of Cyanobacterial ABC Transporters

蓝藻 ABC 转运蛋白的特异性/调节

• 批准号: 7155354
• 负责人: Nicole M Koropatkin
• 金额: $ 4.6万
• 依托单位: DONALD DANFORTH PLANT SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-29 至 2008-09-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7155354
• 关键词: Cyanophyta; X ray crystallography; analytical ultracentrifugation; bacterial proteins; bicarbonates; carbon dioxide; chemical kinetics; gene mutation; hydrolysis; ion transport; iron; membrane transport proteins; microcalorimetry; nitrates; postdoctoral investigator; protein protein interaction; protein structure; protein structure function; site directed mutagenesis; structural biology; surface plasmon resonance; thermodynamics

DESCRIPTION (provided by applicant): The build-up of greenhouse gases in our atmosphere has, and will continue to, lead to a steady increase in the global temperature. A way to halt the further atmospheric accumulation of greenhouses gases, particularly carbon dioxide, is through manipulation of the natural carbon-sequestering mechanisms of aquatic cyanobacteria. One significant factor limiting carbon sequestration in these organisms is the low bioavailability of iron. For the acquisition of bicarbonate and iron, cyanobacteria employ high-affinity ATP-binding cassette (ABC) transporters. These ABC transporters are composed of a periplasmic solute-binding lipoprotein, a cytoplasmic-membrane spanning permease, and an ATPase that powers solute transport. A combination of x-ray crystallography, biochemical and molecular biology techniques will be used to examine both the molecular basis of substrate specificity and transport regulation in the bicarbonate CmpABCD, and the ferric iron FutABC transporters of Synechocystis sp PCC 6803. X-ray crystal structures of the CmpA, CmpC and CmpD proteins will be pursued, as well as a biochemical characterization of the unique multi-domain CmpC protein that is involved in the regulation of bicarbonate uptake. Both thermodynamic and enzymatic techniques will be employed to investigate the interactions between the ATPase domains of CmpC and CmpD. The FutABC transporter will be used to ask the question of whether the membrane permease and ATPase components of ABC transporters plays a role in solute recognition. The solute-binding specificity of the ferric-binding protein FutA1 will be altered in order to test whether the FutBC machinery can accept alternate metal ions. These experiments will involve genetic manipulation of Synechocystis for the purpose of testing metal ion acquisition through FutBC.

描述（由申请人提供）：我们大气中的温室气体的积累已经并且将继续导致全球温度稳定升高。阻止温室气体（尤其是二氧化碳）进一步大气积累的一种方法是操纵水生蓝细菌的天然碳序列机制。这些生物体中碳固执的一个重要因素是铁的生物利用度低。为了获取碳酸氢盐和铁，蓝细菌采用了高亲和力ATP结合盒（ABC）转运蛋白。这些ABC转运蛋白由周质溶质结合脂蛋白，细胞质膜跨度渗透膜和抗溶质转运的ATPase组成。 X射线晶体学，生化和分子生物学技术的结合将用于检查碳酸氢盐CMPABCD中底物特异性的分子基础和运输调节，以及ferric Iont futabc futabc futabc sp pcc pcc 6803。以及参与调节碳酸氢盐摄取的独特多域CMPC蛋白的生化表征。热力学和酶促技术都将用于研究CMPC和CMPD的ATPase结构域之间的相互作用。 FUTABC转运蛋白将用于询问一个问题，即ABC转运蛋白的膜渗透酶和ATPase成分是否在溶质识别中起作用。为了测试FUTBC机械是否可以接受替代金属离子，将改变铁结合蛋白Futa1的溶质结合特异性。这些实验将涉及对综合藻的基因操纵，以通过FUTBC测试金属离子。