The changes in conformation of (Na+ K+)-ATPase from rat brain membranes are accompanied by changes of protein segment movements in the nanosecond range.
Differential polarized phase fluorometry of fluorescein-5-isothiocyanate (FITC) showed that the activation of (Na,K)-ATPase in crude plasma membranes from rat brain by 10 mmol.l-1 K+ and 100 mmol.l-1 Na+ significantly increased the rotational relaxational rate (R) of enzyme-bound FITC. This increase was blocked by both ouabain (0.1 mmol.l-1) and vanadate (0.1 mmol.l-1). In the absence of ATP, R was increased less after adding of 10 mmol.l-1 K+ to the membranes. The shifts in the nanosecond movements of the protein segments measured as R during the activation of (Na,K)-ATPase suggest that this type of movement might be of some functional importance.
Amler
E
E
Institute of Physiology, Czechoslovak Academy of Sciences, Prague.
Teisinger
J
J
Svoboda
P
P
Vyskocil
F
F
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D002540:Cerebral Cortex / Q000201:enzymology; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins; D005456:Fluorescent Dyes; D007700:Kinetics; D011487:Protein Conformation; D051381:Rats; D011919:Rats, Inbred Strains; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013861:Thiocyanates
D005452:Fluoresceins; D005456:Fluorescent Dyes; D013861:Thiocyanates; D000254:Sodium-Potassium-Exchanging ATPase; D016650:Fluorescein-5-isothiocyanate