Construction Of Peptide-based Artificial Enzymes With Photo-switchable Activity

In this study,a peptide-based artificial hydrolase Azo-Gly-Phe-Gly-His with photo-switchable activity was fabricated.In addition,a metal emulated enzyme with redox activity was obtained through the coordination of metal ions(Cu^?,Fe^?)and histidine in the peptide molecule.The structures,morphologies,catalytic activities and photoresponses of artificial enzymes were characterized by various analytical and characterization methods.The conclusions can be drawn as follows:?1?For peptide-based artificial hydrolase system:Through intermolecular hydrogen bonding interaction and?-?stacking,Azo-GFGH is assembled into nanofibers with a secondary structure of the antiparallel?-sheet by which the basicity of imidazole was enhanced,and the hydrophobic microenvironment was obtained.As a result,we obtained a more favorable hydrolytic activity.?2?For peptide-based artificial metalloenzyme system:The peptide Azo-GFGH was able to coordinate with metal ions(Cu^?,Fe^?),then affected the interaction between the peptides in some degree.The co-assembly was thin fibrous with a secondary structure of?-sheet.The peptide-based artificial metal emulated enzyme can accelerate the catalytic rate of free Cu^? and Fe^?,because the coordination of imidazole can stabilize the metal ions.?3?Photo-switchable activity of peptide assembly artificial enzyme:The azobenzene group can change from a trans-to a cis-configuration when irradiated by UV light.Based on this photo-responsive property,the microstructure,secondary structure of the mimic enzyme can be reversibly controlled using UV and visible light,and then lead to the reversible activity declined during the repeated switches.As a result,the activities of peptide assembly artificial enzyme can be reversibly controlled.