Helical Sulfono-γ-AApeptides with Aggregation-Induced Emission and Circularly Polarized Luminescence

• DOI: 10.1021/jacs.9b05329
• Publication Date: 2019-07-23T19:38:27Z
• Authors: Yan Shi; Guangqiang Yin; Zhiping Yan; Peng Sang; Minghui Wang; Robert Brzozowski; Prahathees Eswara; Lukasz Wojtas; Youxuan Zheng; Xiaopeng Li; Jianfeng Cai
• Keywords: Methicillin-Resistant Staphylococcus aureus; Protein Conformation, alpha-Helical; Microbial Sensitivity Tests; 02 engineering and technology; Fluorescence; Anti-Bacterial Agents; Stilbenes; Escherichia coli; Sulfones; Protein Multimerization; Peptides; Protein Structure, Quaternary; 0210 nano-technology; Bacillus subtilis; Fluorescent Dyes

Aggregation-induced emission (AIE) was intensively studied because of packing of small molecules and polymers; however, mid-molecular-weight (1000-3000) molecular scaffold containing a precise number of AIE luminogens is rare. Herein, we report the investigation of three tetraphenylethylene (TPE)-modified sulfono-γ-AApeptides in which multiple TPE moieties are conjugated to the chiral right-handed helical peptidomimetic backbone as functional side chains. The crystal structure of the TPE-α/sulfono-γ-AA peptide 1 demonstrates that because of the rigid helical scaffold of the TPE-α/sulfono-γ-AA peptides, the intramolecular rotations of the TPE with short linker are restricted, therefore leading to the boosted fluorescent emission in solution. Peptides 2 and 3 exhibit aggregation-induced emission enhancement (AIEE), possibly because of the combination of both AIE and rotation restriction. Moreover, because of their preoriented assembly induced by the right-handed helical scaffold, these emissive chiral luminogens show effective circularly polarized luminescence signals with high dissymmetry factor glum. Finally, the amphiphilic nature of TPE-α/sulfono-γ-AA peptides could enable them to penetrate the bacterial membranes and exhibit strong fluorescence. Their antimicrobial activity and labeling-free character could further augment their potential applications in both materials and biomedical sciences.