Mass Spectrometric Identification of Antimicrobial Peptides from Medicinal Seeds.

Tessa B. Moyer,Amanda M. Brechbill,Leslie M. Hicks

doi:10.3390/molecules26237304

Tessa B. Moyer, Amanda M. Brechbill + Show 1 more

Open Access

https://doi.org/10.3390/molecules26237304

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Abstract

Traditional medicinal plants contain a variety of bioactive natural products including cysteine-rich (Cys-rich) antimicrobial peptides (AMPs). Cys-rich AMPs are often crosslinked by multiple disulfide bonds which increase their resistance to chemical and enzymatic degradation. However, this class of molecules is relatively underexplored. Herein, in silico analysis predicted 80–100 Cys-rich AMPs per species from three edible traditional medicinal plants: Linum usitatissimum (flax), Trifolium pratense (red clover), and Sesamum indicum (sesame). Bottom-up proteomic analysis of seed peptide extracts revealed direct evidence for the translation of 3–10 Cys-rich AMPs per species, including lipid transfer proteins, defensins, α-hairpinins, and snakins. Negative activity revealed by antibacterial screening highlights the importance of employing a multi-pronged approach for AMP discovery. Further, this study demonstrates that flax, red clover, and sesame are promising sources for further AMP discovery and characterization.

Highlights

Plants are sessile organisms unable to flee from abiotic and biotic stresses and must produce a diverse array of defensive compounds [1]
Prediction of antimicrobial peptides (AMPs) from genomes represents the pool of peptides that could be detected from L. usitatissimum [27], T. pratense [28], and S. indicum [29] samples; as plants are known to differentially express these peptides based on environmental and developmental conditions [13,14], we expected to only identify a subset within the medicinal plant seed extracts
In silico predictions revealed 80–100 putative AMPs within the genome of each species. These predictions represent the total pool of predicted peptides that possess the cysteine motifs characteristic of antimicrobial peptide families and could be expressed by these plants

Summary

Introduction

Plants are sessile organisms unable to flee from abiotic and biotic stresses and must produce a diverse array of defensive compounds [1]. Traditional medicines often leverage the activities of these natural products to treat a wide range of diseases [2]. While small-molecule natural products are generally better characterized than their peptide counterparts, investigation of medicinal plant extracts through the analytical lens for larger peptide-like biomolecules can reveal novel antimicrobial peptides (AMPs). Endogenous AMPs are usually small (

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