Studies of cytochrome c oxidase-driven H+-coupled phosphate transport catalyzed by the Saccharomyces cerevisiae Pho84 permease in coreconstituted vesicles

The proton-coupled Pho84 phosphate permease of Saccharomyces cel cerevisiae , overexpressed as a histidine-tagged chimera in Escherichia coli, was dete rgent-solubilized, purified, and reconstituted into proteoliposomes. Proteo liposomes containing the Pho84 protein were fused with proteoliposomes cont aining purified cytochrome c oxidase from beef heart mitochondria. Both com ponents of the coreconstituted system were functionally incorporated in tig htly sealed membrane vesicles in which the cytochrome c oxidase-generated e lectrochemical proton gradient could drive phosphate transport via the prot on-coupled Pho84 permease. The metal dependency of transport indicates that a metal-phosphate complex is the translocated substrate.