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

Langmuir

Department of Material Chemistry, Graduate School of Engineering , Kyoto University Kyoto-Daigaku-Katsura, Nishikyo-ku , Kyoto 615-8510 , Japan.

Published: June 2019

An amphiphilic polypeptide, poly(sarcosine)- b-(l-Leu-Aib) (SL16), was reported to self-assemble into vesicles. A GxxxG motif, which is known to induce helix dimerization, is incorporated into the hydrophobic helical block of SL16 to synthesize poly(sarcosine)- b-(l-Leu-Aib)-(Gly-Aib-l-Leu-Aib-Gly-Aib)-(l-Leu-Aib) (SG16). SG16 shows helix association in ethanol at a high concentration and low temperatures, which is not observed with SL16. SG16 self-assembles into vesicles, but are found to be more susceptible to rupture by the addition of Triton X-100 than SL16 vesicles. A mixture of SL16 and SG16 self-assembles into small sheets and micelles likely because of mismatch of the modes of helix association arising from sterical accommodation of iso-butyl groups at the helix-helix interface.

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http://dx.doi.org/10.1021/acs.langmuir.9b00620DOI Listing

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