Friction-mediated dynamic disordering of phospholipid membrane by mechanical motions of photoresponsive molecular glue: Activation of ion permeation

Abstract

A water-soluble photoresponsive molecular glue, Azo-18Glue, consisting of a photochromic azobenzene core and two adhesive dendritic wedges with a total of 18 peripheral guanidinium ion (Gu+) pendants tightly adheres to the surface of a phospholipid membrane, even in buffer, via a multivalent salt-bridge formation with phosphate anions. A photomechanical motion of adhering Azo-18Glue possibly gives rise to dynamic structural disordering of the phospholipid membrane and activates transmembrane ion permeation. In sharp contrast, no activation of ion permeation results when poorly adhesive Azo-6Glue carrying only six Gu+ pendants is used in place of Azo-18Glue. © 2012 American Chemical Society.