Concentration Threshold and Amplification Exhibited by a Helicene Oligomer during Helix-Dimer Formation: A Proposal on How a Cell Senses Concentration Changes of a Chemical

Abstract

Sulfonamidohelicene tetramer (M)-1 exhibits a concentration threshold and amplification phenomena in solution during helix-dimer formation from a random-coil. The (M)-tetramer is a random-coil below a threshold concentration, and the concentration of the helix-dimer is irreversibly amplified once the threshold concentration is exceeded. For example, a 15 % increase in (M)-tetramer total concentration from 0.6 to 0.7mM induces an 8-foldAR increase in the concentration of the helix-dimer, being 8:0.15=53-fold amplification, under temperature oscillation conditions between 47 and 49°C. Experiments without oscillation also exhibit concentration amplification. The threshold and amplification phenomenon involves concentration hysteresis, being away from equilibrium, and self-catalysis. On the basis of this study, a proposal on how a biological cell senses concentration changes of a chemical substance is provided. Concentration change: Sulfonamidohelicene tetramer (M)-1 exhibits a concentration threshold and amplification phenomena in solution. A proposal on how a biological cell senses concentration changes of a chemical substance in cells is provided (see scheme; Boc=tert-butoxycarbonyl).