Membrane association and conformational change of palmitoylated GoK

Bovine brain GoK was specifically palmitoylated in vitro. The apparent dissociation constant for depalmitoylated GoK (dGoK) was 0.273 WM, while that for palmitoylated GoK (pGoK) was 5.77 nM. The dissociation rate constant (K21) and dissociation half-life for dGoK were 8.4U1034 min and 825 min respectively, while no significant dissociation of pGoK was detected. The limiting membrane insertion pressures for pGoK and dGoK were 44.4 mN/m and 41.3 mN/m respectively. These data suggested that palmitoylation facilitated the membrane association of GoK. Conformational changes of dGoK and pGoK detected by monitoring fluorescence spectra and fluorescence quenching were significantly different after they were associated with the membrane. It was suggested that conformational changes of GoK upon membrane association might be related to regulation of GoK signaling by palmitoylation. ß 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.