CALCIUM RESPONSIVE 2-DIMENSIONAL MOLECULAR ASSEMBLING OF LIPID-CONJUGATED CALMODULIN

Calmodulin (CaM), a calcium ion sensitive protein, was conjugated with dioctadecyldimethylammonium bromide and subsequently assembled into a monolayer at the air-water interface using the LB method. The lipid-c onjugated calmodulin (LCC) retains its calcium sensitivity, determined from the changes in the area-pressure isotherm of the monolayer obtai ned at the air-water interface. The functionality of this protein asse mbly was characterized by the activation of phosphodiesterase (PDE), a CaM responsive enzyme. The enzyme activity of PDE coupled with LCC at the air-water interface was measured by using the enzymatic method. I t was found that LCC retained its enzyme activity modulating function of calmodulin, which is triggered by calcium ions. This characteristic plays an important role in fabricating molecular assembly of proteins which have a cooperative interaction at the molecular level.