p-octiphenyl β-barrels with ion channel and esterase activity

[GRAPHICS] Design, synthesis, and esterase and ion channel activity of a novel barrel-stave supramolecule with hydrophobic exterior and histidine-rich interior are reported. Voltage-dependent binding of pyrenyl-8-oxy-1,3,6-trisulfonates by histidines within p-octiphenyi,beta -barrels (and not monomers) via ionic (and not hydrophobic) interactions (K-D, K-l, K-M < 1 muM) is the basis for superb esterolytic proficiency up to (k(cat)/K-M)/k(uncat) = 9.6 x 10(5) in water and bilayer membranes. The conductance of labile ion channels formed in planar bilayer membranes is shown to be reduced by 8-hydroxypyrene-1,3,6-trisulfonate on the single- and multichannel level.