Proton Transport and Proton-Motive Force in Prokaryotic Cells
1987; Elsevier BV; Linguagem: Inglês
10.1016/b978-0-12-596935-2.50004-9
AutoresMasamitsu Futai, Tomofusa Tsuchiya,
Tópico(s)Mitochondrial Function and Pathology
ResumoThis chapter discusses proton transport and proton-motive force (Δp) in prokaryotic cells. The vectorial movement of protons plays a central role in bioenergetics. Generation of a substantial Δp has been observed in both growing and nongrowing bacteria, suggesting that a chemi-osmotic mechanism functions in a wide variety of prokaryotes. Bacteria have at least four primary H+ -transport systems capable of forming a Δp. An obvious advantage of using bacteria is that genetic techniques can be applied easily. Mutants of each subunit have been isolated and the gene cluster for the enzyme has been cloned from E. coli. The primary structures of all the subunits of E. coli H+ -ATPase were determined from the DNA sequence and the "essential" residues in catalysis and proton transport were identified. The chapter discusses bacteriorhodopsin, which is the most extensively studied proton pump. The amino acid sequence and the higher ordered structure of this light-dependent proton pump are known presently.
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