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Solubilization and functional reconstitution of the DCCD-sensitive Na+H+-antiporter from Halobacterium halobium

1990; Elsevier BV; Volume: 170; Issue: 3 Linguagem: Inglês

10.1016/0006-291x(90)90541-t

1090-2104

Tetsuya Konishi, Naoyuki Murakami,

Neuroscience of respiration and sleep

Na+H+ exchange activity was solubilized from Halobacterium halobium with octyl-β-D-glucoside (OG) and was reconstituted into the bacteriorhodopsin incorporated liposomes (BR-liposomes) by the detergent-dialysis method. Light illumination stimulated uphill 22Na+ uptake into the reconstituted conjugate proteoliposomes. The 22Na+ uptake was FCCP-sensitive and was dependent on the amounts of OG-extract applied. On the other hand, the proteoliposomes reconstituted with the membrane fraction pretreated with N,N′-dicyclohexylcarbodiimide (DCCD) did not exhibit the light-dependent 22Na+ uptake, thus, DCCD-sensitive. When the reconstituted proteoliposome was incubated with [14C]DCCD, radio-labels appeared slightly on 50K but mainly on 11K-Dalton component, which are the same components labeled in the intact membrane vesicles. It is concluded that halobacterial DCCD-sensitive Na+H+-antiporter was solubilized and reconstituted in the conjugate BR-liposomes with preserved functional unit.