Dramatic morphological changes in liposomes induced by peptide nanofibers reversibly polymerized and depolymerized by the photoisomerization of spiropyran

• Published in: Frontiers in molecular biosciences Vol. 10; p. 1137885
• Main Authors: Liang, Yingbing, Ogawa, Shigesaburo, Inaba, Hiroshi, Matsuura, Kazunori
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 30.03.2023
• Subjects: liposome; Molecular Biosciences; peptide nanofiber; photoisomerization; polymerization/depolymerization; self-assembly; spiropyran; polymerization/depolymerization; spiropyran; self-assembly; artificial cytoskeleton; photoisomerization; merocyanine; liposome; peptide nanofiber
• ISSN: 2296-889X; 2296-889X
• DOI: 10.3389/fmolb.2023.1137885

Cytoskeletons such as microtubules and actin filaments are natural protein assemblies, which dynamically control cellular morphology by reversible polymerization/depolymerization. Recently, the control of polymerization/depolymerization of fibrous protein/peptide assemblies by external stimuli has attracted significant attention. However, as far as we know, the creation of an "artificial cytoskeleton" that reversibly controls the polymerization/depolymerization of peptide nanofiber in giant unilamellar vesicles (GUVs) has not been reported. Here, we developed peptide nanofiber self-assembled from spiropyran (SP)-modified -sheet-forming peptides, which can be reversibly polymerized/depolymerized by light. The reversible photoisomerization of the SP-modified peptide (FKFEC KFE) to the merocyanine-peptide (FKFEC KFE) by ultraviolet (UV) and visible light irradiation was confirmed by UV-visible spectroscopy. Confocal laser scanning microscopy with thioflavin T staining and transmission electron microscopy of the peptides showed that the SP-peptide formed -sheet nanofibers, whereas the photoisomerization to the merocyanine-peptide almost completely dissociated the nanofibers. The merocyanine peptide was encapsulated in spherical GUVs comprising of phospholipids as artificial cell models. Interestingly, the morphology of GUV encapsulating the merocyanine-peptide dramatically changed into worm-like vesicles by the photoisomerization to the SP-modified peptide, and then reversibly changed into spherical GUV by the photoisomerization to the MC-modified peptide. These dynamic morphological changes in GUVs by light can be applied as components of a molecular robot with artificially controlled cellular functions.