1 research outputs found
Photoreconfigurable Supramolecular Nanotube
A photoreconfigurable bionanotube
was developed by Mg<sup>2+</sup>-induced supramolecular polymerization
using GroEL<sub>SP</sub>, a mutant barrel-shaped chaperonin protein
bearing multiple photochromic spiropyran (SP) units at its apical
domains. Upon exposure to UV light, the nonionic SP units isomerize
into ionic merocyanine (MC) to afford GroEL<sub>MC</sub>, which is
capable of polymerizing with MgCl<sub>2</sub>. The resultant nanotube
(NT) is stable as a result of multiple MC···Mg<sup>2+</sup>···MC bridges but readily breaks up into short
NTs, including monomeric GroEL<sub>SP</sub>, by the reverse (MC →
SP) isomerization mediated by visible light. When this scission mixture
is exposed to UV light, long NTs are reconfigured. A Förster
resonance energy transfer (FRET) study revealed that NTs in the dark
maintain their sequential integrity. However, when exposed to visible
and UV light successively, the NTs lose their sequential memory as
a result of intertubular reshuffling of the constituent GroEL<sub>MC</sub> units