Uniformly oriented bacterial F₀F₁‐ATPase immobilized on a semi‐permeable membrane: a step towards biotechnological energy transduction

Abstract

The immobilization of F(0)F(1)-ATPase in uniform orientation is reported. The biotinylated and histidine-tagged subunits of the bacterial F(0)F(1)-ATPase complex were used for immobilization of the complex on artificial semi-permeable membranes resulting in 88+/-7.8 and 72+/-5.2% coupling of the enzymes. The immobilized enzymes retained over 90% activity. The immobilized ATPase/synthase was used for generation of ATP from ADP and P(i) at the expense of electrochemical potential energy. The re-usability, ratio of amount of enzyme immobilized to enzymic activity conferred on the membranes, ATP synthesized by assembled system and suitability of ATP generated for use in coupled enzymic reactions were determined.

H2‐Fueled ATP Synthesis on an Electrode: Mimicking Cellular Respiration

“…Great progress in immobilizing enzymes has allowed the exploitation of their substrate specificity to catalyze chemical reactions for industrial applications5 and to develop biosensors with great selectivity and capacity to detect analytes 6. However, to mimic and utilize the vectorial ion movement required for the generation of electrochemical gradients in living cells, both spatial control over the assembly of the participating proteins,7 and the presence and maintenance of two independent ion‐impermeable compartments are required 8. Liposomes,9 where a lipid bilayer separates the inner content from the outer solution, have been used as model systems to couple light energy to different biochemical reactions.…”