RESUMO
Bacteriorhodopsin (bR) is the prototype of an integral membrane protein with seven membrane-spanning alpha-helices and serves as a model of the G-protein-coupled drug receptors. This study is aimed at reaching a greater understanding of the role of amine local anesthetic cations on the proton transport in the bR protein, and furthermore, the functional role of "the cation" in the proton pumping mechanism. The effect of the amine anesthetic cations on the proton pump in the bR blue membrane was compared with those by divalent (Ca2+, Mg2+ and Mn2+) and monovalent metal cations (Li+, Na+, K+ and Cs+), which are essential for the correct functioning of the proton pumping of the bR protein. The results suggest that the interacting site of the divalent cation to the bR membrane may differ from that of the monovalent metal cation. The electric current profile of the bR blue membrane in the presence of the amine anesthetic cations was biphasic, involving the generation and inhibition of the proton pumping activity in a concentration-dependent manner. The extent of the regeneration of the proton pump by the additives increased in the order of monovalent metal cationAssuntos
Aminas/farmacologia
, Anestésicos/farmacologia
, Bacteriorodopsinas/metabolismo
, Membrana Celular/efeitos dos fármacos
, Bacteriorodopsinas/antagonistas & inibidores
, Cátions
, Halobacterium salinarum/efeitos dos fármacos
, Inibidores da Bomba de Prótons
, Prótons
, Membrana Purpúrea/efeitos dos fármacos