Phosphate Transport in Biological Systems

无机磷和三磷酸腺苷在地球表面参与的化学反应比除水以外的任何其他化合物都多。磷酸盐进入真核细胞及其细胞器至少由两种不同类型的转运系统催化，一种是Na+/P转运体，另一种是H+/P转运体。过去在NSF的支持下，H+/P转运蛋白被鉴定为32-35 kDa的蛋白，其纯化、重组、克隆、测序、在大肠杆菌中表达，并导入分离的线粒体中。在赠款期间，未来的具体目标是6倍，并将是。%确定H+/PI转运体在其天然膜环境中的功能形式是单体还是更高有序的低聚物。对H+/PI转运蛋白全长基因进行功能性表达，并验证其膜拓扑结构。在功能表达的转运蛋白中引入定点突变和随机突变，以确定参与转运的候选氨基酸。开展可能对提供有关H+/PI转运体的三维结构信息有价值的研究。确定同源H+/PI转运体在植物和动物细胞中的表达程度。比较H+/PI转运蛋白基因(S)在植物和动物细胞中表达的调控事件。

Inorganic phosphate and ATP are involved in more chemical reactions on the earth's surface than any other compound except water. Phosphate entry into eukaryotic cells and into their organelles is catalyzed by at least two distinct types of transport system, one, a Na+/P transporter and the other a H+/P transporter. Past work supported by NSF resulted in the identification of the H+/P transporter as a 32-35 kDa protein, its purification, reconstitution, cloning, sequencing, expression in E. coli, and import into isolated mitochondria. Future Specific Aims during the grant period are 6-fold and will be to. %%% Establish whether the functional form of the H+/Pi transporter in its native membrane environment is a monomer or a higher ordered oligomer. Express functionally the full length cDNA of the H+/Pi transporter and verify its membrane topology. Introduce both site directed and random mutations in the functionally expressed transporter in order to identify candidate amino acids involved in transport. Initiate studies which may prove valuable in supplying 3-Dimensional structural information about the H+/Pi transporter. Determine to what extent homologous H+/Pi transporters are expressed in plant and animal cells. Compare the regulatory events involved in the expression of H+/Pi transporter Gene(s) in plant and animal cells.