Subunits Coupling H+ Transport and ATP Synthesis in the Escherichia coli ATP Synthase

The vacuolar H+-ATPase: a universal proton pump of eukaryotes

“…Using hybrid enzymes comprising F " and F o from H + -and Na + -translocating F-ATPases respectively, it has been possible to show that cation discrimination is solely the property of F o [207]. Mutational analysis has furthermore shown that subunit c contributes to cation discrimination [208], as might be expected from its pivotal role in ion translocation. Similar reconstitution and mutation studies have yet to be carried out on H + -and Na + -pumping V-ATPases.…”

Thermophilic F1-ATPase Is Activated without Dissociation of an Endogenous Inhibitor, ε Subunit

“…The ␦ and ⑀ subunits, together with ␥ subunit, are considered to form a stalk portion that connects F 1 -ATPase to membraneembedded proton channel, Fo (13)(14)(15). ␦ subunit has an ␣-helical, elongated structure (16 -18), and close proximity to the N-terminal region of ␣ subunit (19 -23) and Fo subunit (24) has been suggested.…”

Intragenic and intergenic suppression of the Escherichia coli ATP synthase subunit a mutation of Gly-213 to Asn: functional interactions between residues in the proton transport site

“…Evidence for conformational coupling is suggested by differences in the solution structures of the protonated compared with the unprotonated c subunit [10]. Its polar loop, through which coupling is mediated via contacts with the ε [53] and γ [42] subunits, has distinct differences in conformation. The direct structural interactions between the c polar loop and the ε (δ in mitochondrial nomenclature) and γ subunits have recently been confirmed by the crystal structure of the yeast F o F " complex [11].…”

“…Several mutations in key positions that block the transmission of conformational information have been identified. Amino acid substitutions in the interfaces between the β and γ subunits [43,49], the ε and c subunits [53], the ε and a subunits [55] and the γ and c subunits [42] perturb proper transmission and result in inefficient coupling.…”

“…The carboxylic acid of cAsp-61, which is located near the middle of the bilayer, is essential for transport function [19]. Several residues in proximity to cAsp-61 seem to create an environment that defines the properties of the carboxylic acid that are required for proton transport [10,[20][21][22][23][24][25]. In subunit a, the replacement of many residues disrupts transport function ; however, only one, aArg-210, has proved to be essential for coupled transport because any replacement, including Lys, causes complete loss of function [26][27][28][29].…”