B. Ghebremariam et S. Matile, Chiroptical rhythmicity, part 2. Evidence for signal transduction by stereoselective ion pair formation at the membrane/water interface, ENANTIOMER, 4(2), 1999, pp. 131-139
The initiation mechanism of chiroptical rhythmicity, a novel chiroptical ph
enomenon (Ghebremariam and Matile preceding contribution), was investigated
by exploring the functionality of five structural analogs of the inducing
L-His ligand. Disappearance of chiroptical rhythmicity with L-His methyl es
ters as well as with D-His implied that stereoselective ion Fair formation
between carboxylate anion of L-His bound at the membrane/water interface an
d ammonium cations of phosphatidylcholine is essential for signal transduct
ion to the hydrophobic core of the membrane. It was further shown that "H"
aggregation of the asymmetric septi(p-phenylene) chromophore induced by mul
tivalent L-His (i.e., poly-L-His) exceeds the extent required for chiroptic
al rhythmicity by far and ultimately results in the formation of achiral he
rringbone lattices.