3F1058 OBSERVATION OF TRANSMEMBRANE PROTEIN BY HIGH SPEED ATOMIC FORCE MICROSCOPY : BACTERIORHODOPSIN D85S MUTANT, A CHLORIDE PUMP(Membrane Proteins,Oral Presentation)

Abstract

Non-detergent sulfobetaines (NDSBs) are known to stabilize many proteins, and we have found that NDSBs, in particular NDSB-256, potently stabilize rn2 muscarinic acetylcholine receptor <m2-R). Here we anatyzed the mechanisms whereby NDSB-256 stabilizes m2-R. The apparent dissociation constant Kd ofNDSB-256 and m2-R, as determined by the NDSB-256 concentration dependence of the denaturation time constant of m2R at 50 degree, was smaller than the inhibjtion constant Ki ofNDSB-256, as determined by competitive inhibition of [3H]QNB-bjnding to m2R. These observations suggest