1. Probing protein sequences as sources for encrypted antimicrobial peptides.
- Author
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Brand GD, Magalhães MT, Tinoco ML, Aragão FJ, Nicoli J, Kelly SM, Cooper A, and Bloch C Jr
- Subjects
- Amino Acid Sequence, Anti-Bacterial Agents chemistry, Antifungal Agents chemistry, Basidiomycota drug effects, Calorimetry, Differential Scanning, Escherichia coli drug effects, Microbial Sensitivity Tests, Molecular Sequence Data, Peptide Fragments chemistry, Peptide Fragments genetics, Plant Diseases microbiology, Plant Proteins chemistry, Plant Proteins genetics, Principal Component Analysis, Protein Structure, Secondary, Pseudomonas aeruginosa drug effects, Sequence Analysis, Protein, Glycine max genetics, Glycine max microbiology, Spores, Fungal drug effects, Staphylococcus aureus drug effects, Anti-Bacterial Agents pharmacology, Antifungal Agents pharmacology, Peptide Fragments pharmacology, Plant Proteins pharmacology
- Abstract
Starting from the premise that a wealth of potentially biologically active peptides may lurk within proteins, we describe here a methodology to identify putative antimicrobial peptides encrypted in protein sequences. Candidate peptides were identified using a new screening procedure based on physicochemical criteria to reveal matching peptides within protein databases. Fifteen such peptides, along with a range of natural antimicrobial peptides, were examined using DSC and CD to characterize their interaction with phospholipid membranes. Principal component analysis of DSC data shows that the investigated peptides group according to their effects on the main phase transition of phospholipid vesicles, and that these effects correlate both to antimicrobial activity and to the changes in peptide secondary structure. Consequently, we have been able to identify novel antimicrobial peptides from larger proteins not hitherto associated with such activity, mimicking endogenous and/or exogenous microorganism enzymatic processing of parent proteins to smaller bioactive molecules. A biotechnological application for this methodology is explored. Soybean (Glycine max) plants, transformed to include a putative antimicrobial protein fragment encoded in its own genome were tested for tolerance against Phakopsora pachyrhizi, the causative agent of the Asian soybean rust. This procedure may represent an inventive alternative to the transgenic technology, since the genetic material to be used belongs to the host organism and not to exogenous sources.
- Published
- 2012
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