Identification and Characterization of Bioactive Cyclotides in Viola odorata using PepSAVI-MS

Antimicrobial resistance (AMR) is present in every country worldwide and has a direct impact on global health, agriculture and economy. Treatment of common bacterial, viral and fungal infections is becoming increasingly challenging as new mechanisms for AMR develop, accelerated by the misuse and overuse of antimicrobial drugs. Botanically‐derived bioactive peptides are an attractive solution to the ongoing deficit of new antimicrobial compounds, with the ability to be highly selective, potent, and inexpensive to produce on a large scale. Our lab has developed the PepSAVI‐MS ( S tatistically‐guided bio A ctive Pep tides prioritized VI a M ass S pectrometry) pipeline, an adaptable method for the analysis of natural product libraries to rapidly identify bioactive peptides. Using PepSAVI‐MS to screen the cyclotide‐rich botanical species Viola odorata against a variety of human and plant pathogens, we have identified several putative, uncharacterized cyclotides. Cyclotides are a class of cyclic, disulfide‐rich, plant‐derived peptides that boast a diverse range of potent antimicrobial bioactivities, indicating a highly stable, evolvable scaffold. Additionally, we have identified novel bioactivities of a known nematocidal V. odorata cyclotide, Cycloviolacin O8 (cyO8), including anticancer activity against PC3 prostate, MDA‐MB‐231 breast, and OVCAR ovarian cancer cell lines, and for the first time in literature, cyclotide antifungal activity against the common fungal pathogen Fusarium graminearum . Furthermore, to address the identity of the putative, traditionally difficult‐tosequence V. odorata cyclotide species, we demonstrate a proof‐of‐principle 193 nm ultraviolet photodissociation (UVPD) mass spectrometry approach using cyO8 to elucidate the fragmentation efficiency of this information‐rich technique. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .