Search results for "Proton motive force"
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Ions channels/transporters and chloroplast regulation.
2015
International audience; Ions play fundamental roles in all living cells and their gradients are often essential to fuel transports, to regulate enzyme activities and to transduce energy within and between cells. Their homeostasis is therefore an essential component of the cell metabolism. Ions must be imported from the extracellular matrix to their final subcellular compartments. Among them, the chloroplast is a particularly interesting example because there, ions not only modulate enzyme activities, but also mediate ATP synthesis and actively participate in the building of the photosynthetic structures by promoting membrane-membrane interaction. In this review, we first provide a comprehen…
The Low-Affinity ATP Binding Site of the Escherichia coli SecA Dimer Is Localized at the Subunit Interface
1997
The homodimeric SecA protein is the ATP-dependent force generator in the Escherichia coli precursor protein translocation cascade. SecA contains two essential nucleotide binding sites (NBSs), i.e., NBS1 and NBS2 that hind ATP with high and low affinity, respectively. The photoactivatable bifunctional cross-linking agent 3'-arylazido-8-azidoadenosine 5'-triphosphate (diN(3)ATP) was used to investigate the spatial arrangement of the nucleotide binding sites of SecA, DiN(3)ATP is an authentic ATP analogue as it supports SecA-dependent precursor protein translocation and translocation ATPase, UV-induced photo-cross-linking of the diN(3)ATP-bound SecA results in the formation of stable dimeric s…