2-DIMENSIONAL MOLECULAR ASSEMBLING OF CALMODULIN-MELITTIN AT THE AIR-WATER-INTERFACE

The protein molecular assembly of calmodulin (CaM) mixed with melittin , an amphiphilic molecule, was assembled at the air-water interface by using the Langmuir-Blodgett technique. The changes in the surface pre ssure of the mixed protein monolayer were measured in the presence and absence of calcium ions in the subphase. A molecular coordination bet ween both types of molecules appeared to occur in the monolayer at the air-water interface; This molecular coordination was further examined by labeling 6-p-toluidino-2-naphthalenesulfonyl chloride (CH3C6H4NHC1 0H6SO2Cl or TNS-Cl), a hydrophobic probe, to melittin and observing th e change in fluorescence intensity in the presence and absence of calc ium ion in the subphase. It was shown that molecular assemblies of cal modulin with its target molecule had a coordinated function that chang ed the structure of the monolayer at the air-water interface in a calc ium ion responsive manner.