Supramolecular structures generated by a p- tert-butylphenylamide derivative of deoxycholic acid. from planar sheets to tubular structures through helical ribbons

摘要

The formation of supramolecular structures initiated by a p-tert-butylphenylamide derivative of deoxycholic acid (Na-t-butPhDC) is investigated. At 1.18 mM concentration of Na-t-butPhDC and 37 °C, initial flat ribbons are observed which self-transform into helical ribbons (with a mean pitch angle of 47 ± 6°) which finally originate molecular tubes with an external diameter of 241 ± 28 nm. Most of the molecular tubes show helical markings with a pitch angle value of 45 ± 4°, in full agreement with predictions of simple models based on chiral elastic properties of the membrane. A lateral association mechanism is proposed to account for the growth of the external diameter (from 225 ± 32 to 546 ± 59 nm) of tubes with time at 3.99 mM.