Self-Assemblies of Triskelion A₂B-Type Amphiphilic Polypeptide Showing pH-Responsive Morphology Transformation

Abstract

A pH-responsive rolled-sheet morphology was prepared from a triskelion A(2)B-type amphiphilic polypeptide having a histidine residue as a pH-responsive unit. The dimensions of the rolled sheet were 85 nm diameter and 210 nm length with a sheet turn number of 2.0 at pH 7.4. Upon decreasing the pH from 7.4 to 5.0, the layer spacing of the rolled sheets was widened from ca. 9 to ca. 19 nm due to electrostatic repulsion caused by histidine protonation. This morphology change occurred reversibly with a pH change between 7.4 and 5.0. The molecular packing in the rolled sheets was shown to be loosened at pH 5.0 on the basis of electron diffraction measurements. The tightness of the rolled sheets was thus controlled reversibly by a pH change due to a single protonation in the amphiphilic polypeptide.

Time-controllable roll-up onset of polythiophene sheets into nanotubes that exhibit circularly polarized luminescence

“…Toroid-and ring-like nanostructures assemble into nanotubes by stacking on top of one another, [33][34][35][36][37] and sheet-like nano-and microstructures roll up into nanotubes that have whirling patterns. [38][39][40][41][42][43] Zipping of the both face to face edgings of the rolled-up sheet results in perfectly tubular shapes. Disk-like nanostructures grow into fragments of the membrane walls of nanotubes.…”

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

“…With decrease in the pH value from 7.4 to 5.0, tubularly rolled-up sheets self-assembled from the A 2 -His-B-type amphiphile widened their layer spacing from ∼9 to ∼19 nm because of electrostatic repulsion between the His residues. 247 As a photosensitive molecular building block, we also synthesized more two amphiphilic molecules (DGlyAzo and TGlyAzo), which comprise azobenzene and oligoglycine hydrogen-bonding moieties (diglycine or triglycine), in addition to the aforementioned MGlyAzo. 51 In contrast to the photoresponsive behavior of MGlyAzo, UV and visible light irradiation to the DGlyAzo-based AZNTs finally converted their shape from tubular to stacked-ring-based nanotube.…”

“…By employing the polypeptides, they investigated the morphological change sensitive to external pH environment. With decrease in the pH value from 7.4 to 5.0, tubularly rolled-up sheets self-assembled from the A 2 -His-B-type amphiphile widened their layer spacing from ∼9 to ∼19 nm because of electrostatic repulsion between the His residues …”

Polypeptoid polymers: Synthesis, characterization, and properties

“…This area represents a fertile ground for research, as it will provide fundamental understanding of the interactions between polypeptoids and immune systems, which is critical for the further development of polypeptoid biomaterials for in vivo applications. poly(E-N-benzyloxycarbonyl-L-lysine), [99] poly(g-benzyl-L-glutamate), [99] poly(g-tert-butyl-L-glutamate), [100] and poly(S-ethylsulfonyl-L-cystine)], [101] PNMG-b-poly(E-caprolactone), [102] PNMG-b-poly[2-(3-butenyl)-2-oxazoline], [57] PNMG-b-(Leu-Aib) n [(Leu-Aib) n : helical peptides], [103][104][105][106][107][108][109][110] PNMG-b-poly(L-lactide) (AB, A 2 B, A 3 B types), [111] dextran-b-PNMG, [112] PEG-b-PNMG, [42] and C n512-18 -PNMG lipopolymers. [113][114][115] Their solution aggregation behavior has been reviewed by Luxenhofer et al [30] and will not be repeated here.…”