Effect of Photoinduced Size Changes on Protein Refolding and Transport Abilities of Soft Nanotubes

Abstract

Self-assembly of azobenzene-modified amphiphiles (Glyn Azo, n=1-3) in water at room temperature in the presence of a protein produced nanotubes with the protein encapsulated in the channels. The Gly2 Azo nanotubes (7 nm internal diameter [i.d.]) promoted refolding of some encapsulated proteins, whereas the Gly3 Azo nanotubes (13 nm i.d.) promoted protein aggregation. Although the 20 nm i.d. channels of the Gly1 Azo nanotubes were too large to influence the encapsulated proteins, narrowing of the i.d. to 1 nm by trans-to-cis photoisomerization of the azobenzene units of the Gly1 Azo monomers packed in the solid bilayer membranes led to a squeezing out of the proteins into the bulk solution and simultaneously enhanced their refolding ratios. In contrast, photoinduced transformation of the Gly2 Azo nanotubes to short nanorings (<40 nm) with a large i.d. (28 nm) provided no further refolding assistance. We thus demonstrate that pertubation by the solid bilayer membrane wall of the nanotubes is important to accelerate refolding of the denatured proteins during their transport in the narrow nanotube channels.

RETRACTED: Supramolecular Nanotube Reactors for Production of Imine Polymers with Controlled Conformation, Size, and Chirality

“…For example, conjugated polymers that exist as random coils in bulk solution take on a 1D extended conformation in nanotubes with narrow channels, whereas the polymers take on an aggregated conformation in wider nanotube channels . In addition, supramolecular nanotubes can not only stabilize the native structures of proteins and double‐stranded DNA under harsh conditions but also accelerate refolding of denatured proteins and formation of oligonucleotide duplexes . However, synthesis of polymers inside nanotube channels has rarely been reported, although nanotubes have been widely utilized as templates for the construction of inorganic and metal nanostructures through sol–gel reactions and reduction of inorganic precursors and metal ions adsorbed on the surfaces of and/or encapsulated in the channels of the nanotubes…”

RETRACTED: Bioreactors Based on Enzymes Encapsulated in Photoresponsive Transformable Nanotubes and Nanocoils End‐Capped with Magnetic Nanoparticles

“…Supramolecular polymer nanotubes, formed by self‐assembly of rationally designed amphiphilic molecules in water, are able to encapsulate and release enzymes and other proteins, which requires precise tuning of the size and surfaces composition of the nanochannels . Nanotubes are useful for qualitative and quantitative analysis of proteins, stabilization of proteins under harsh conditions, acceleration of protein refolding, and mimicking of proteins . The use of nanotubes as solid supports in bioreactors is so far limited because of the disadvantages such as an insufficient fixation of enzymes in addition to a slow diffusion of substrates to the nanochannels encapsulating enzymes.…”

Soft-Matter Nanotubes: A Platform for Diverse Functions and Applications

“…33 The relationship between the inner diameters of nanotubes and guest sizes sensitively affect the features of encapsulation, diffusion/transportation, stabilization, release, and refolding of guest substances including proteins. 35,36,40,51,52,114,115 A typical example was shown by the fact that optimized inner surfaces of SMNTs and the exterior functionalities of a guest protein enable some SMNTs to behave as artificial molecular chaperone. 35,36 Moreover, one recent outstanding advance in new functions that will take place in the interior nanospace is the utilization of a multiwalled LNT as a sample fixation substrate for transmission electron microscopy (TEM) computed tomography (CT).…”

“…35,36,40,51,52,114,115 A typical example was shown by the fact that optimized inner surfaces of SMNTs and the exterior functionalities of a guest protein enable some SMNTs to behave as artificial molecular chaperone. 35,36 Moreover, one recent outstanding advance in new functions that will take place in the interior nanospace is the utilization of a multiwalled LNT as a sample fixation substrate for transmission electron microscopy (TEM) computed tomography (CT). 116,117 It should also be noted that catalytic actions, conducted by metal-coordinated SMNTs 118−122 and MONNs prepared from BBC, 84 give another special examples.…”