ATP synthase subunit

Escherichia coli FiFg ATP Synthase Subunit Organization ... 

Lolkema, J. S., and Boekema, E. J. (2003). The A-type ATP synthase subunit K of Methanopyrus kandleri is deduced from its sequence to form a monomeric rotor comprising 13 hairpin domains. FEBSLett. 543, 47-50. 

Yamada, H., Moriyama, Y., Maeda, M., and Futai, M. (1996). Transmembrane topology of Escherichia coli H(+) -ATPase (ATP synthase) subunit a. FEBS Lett. 390, 34-38. 

N3. Nijtmans, L. G., Henderson, N. S., Attardi, G., and Holt, I. J., Impaired ATP synthase assembly associated with a mutation in the human ATP synthase subunit 6 gene. J. Biol. Chem. 276, 6755-6762 (2001). 

Vacuolar ATP synthase subunit B, brain isoform D in DS Kim et al. 2000b... 

There are three main reasons to suggest a specific function of subunit III in proton translocation. First, Casey et al. [171] showed that modification of this subunit with dicyclohexylcarbodiimide (DCCD) blocks proton translocation, but has little effect on electron transfer. Similar results have been obtained with the reconstituted oxidase from the thermophilic bacterium PS3 [164]. Prochaska et al. [160] showed that DCCD binds mainly to Glu-90 of the bovine subunit III, which is predicted to lie within the membrane domain and hence to be a site analogous to the DCCD binding site in the membranous fj, sector of the ATP-synthase (Fig. 3.8 see also Ref. 85). Since the latter is a part of a proton-conducting channel in ATP synthase, subunit III was thought to have the same function. However, there is one essential difference between the two phenomena. Modification of the membranous glutamic residue in by DCCD leads also to inhibition of ATP hydrolysis in the complex, as expected for two linked reactions. In contrast, DCCD has little or no effect on electron transfer in cytochrome oxidase under conditions where H translocation is abolished. Hence, DCCD cannot simply be judged to block a proton channel in the oxidase. More appropriately, it decouples proton translocation from electron transfer. 

A second pathway to the inner membrane is followed by proteins (e.g., ATP synthase subunit 9) whose precursors contain both a matrix-targeting sequence and internal hydrophobic domains recognized by an inner-membrane protein termed Oxal. This pathway is thought to involve translocation of at least a portion of the precursor into the matrix via the Tom20/22 and Tlm23/17 channels. After cleavage of the matrix-targeting sequence, the protein is in-... 

ATP synthase contains a membrane-spanning domain, sometimes known as the Fo subunit, and a knobby protmsion that extends into the matrix, the Fi subunit. The mechanism of ATP synthase is not what one would naively predict. The Fi ATP synthase subunit can perform its ligase function (making ATP from ADP and phosphate) without proton flow into the matrix however, release of the ATP requires flow of protons through the membrane. 

Fig. 1. Organisation of genes encoding ATP synthase subunits In bacteria and plant chloroplasts.

The scale Is In kllobases, the letters a, b, c, Q, 3, Y. S and e Indicates the ATP synthase subunit encoded In the gene. The letters I and X Indicate genes of unknown function (1,2,7 and H.S. van Walraven, J.E. Walker, unpublished results). Chloroplast c subunit (prime tertron) Is also known as subunit III and chloroplast b as subunit I b contains an Intron (8) b Is a duplicated and diverged form of b. The dashed line signifies that the gene clusters are at least 15 kllobases apart and are separately transcribed. 

SYNTHESIS AND ASSEMBLY OF A CHLOROPLAST ATP SYNTHASE SUBUNIT IN VITRO... 

Synthesis and Assembly of a Chloroplast ATP Synthase Subunit in vitro 811... 

Berggren, K. N. Chernokalskaya, E. Lopez, M. F. Beechem, J. M. Patton, W. F. Comparison of three different fluorescent visuahzation strategies for detecting Escherichia coli ATP synthase subunits after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Proteomics 2001,1, 54—65. 

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