Osmotic-shock-resistant Vesicle Comprising Interdigitated Monolayer of Block Polypeptides

Sterical Recognition at Helix–Helix Interface of Leu-Aib-Based Polypeptides with and without a GxxxG-Motif

“…The mode of helix−helix association of the Leu-Aib-based peptides was reported before (Figure 3, lower). 14 The interdigitated monolayer structure has been proved previously on the basis of the AFM observation. 15 With tilting helix axes with each other, iso-butyl groups from two helices align on a straight line to make the helix association tight.…”

“…13,22−24 The versatile applications of the Leu-Aib-based helices for molecular assemblies in a wide range of morphologies rely on the stable helix association because of the sterical recognition of iso-butyl groups at the helix−helix interface. 14 On the other hand, the GxxxG motif is known to induce helix dimerization, which is often involved in triggering biological signals. Indeed, the Leu-Aib-based helix incorporating the GxxxG motif (SG16) showed preference of helix association in ethanol, whose association was not available for the Leu-Aibbased helix without it.…”

“…11 We have reported that poly(sarcosine)-b-(L-Leu-Aib) 8 (SL16, Figure 1a, upper) self-assembled into vesicles having the membrane core entirely composed of helical peptides without any help of lipids or surfactants. 12 This type of molecular assembly is promising for study of the helix−helix interaction because of the tight association of the helices in the membrane. Accordingly, a novel amphiphilic block polypeptide incorporating the GxxxG motif into the Leu-Aib-based polypeptide is designed: poly(sarcosine)-b-(L-Leu-Aib) 2 -Gly-Aib-L-Leu-Aib-Gly-Aib-(L-Leu-Aib) 3 (SG16, Figure 1a, lower).…”

“…We have reported that poly­(sarcosine)- b -( l -Leu-Aib) 8 (SL16, Figure a, upper) self-assembled into vesicles having the membrane core entirely composed of helical peptides without any help of lipids or surfactants . This type of molecular assembly is promising for study of the helix–helix interaction because of the tight association of the helices in the membrane.…”

Phase-Separated Molecular Assembly of a Nanotube Composed of Amphiphilic Polypeptides Having a Helical Hydrophobic Block

“…18 Consequently, it is considered that the helical blocks associate tightly owing to the good space filling of interdigitated isobutyl side chains from the neighbor helices. 19 As a result, the amphiphilic polypeptide self-assembled into a curved sheet morphology, which easily changes the morphology into a nanotube morphology with temperature. However, a vesicular morphology is more thermodynamically stable than a nanotube morphology by disappearance of the hydrophobic open edges of a nanotube.…”