Eosinophil cationic protein aggregation: identification of an N-terminus amyloid prone region.
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Torrent M, Odorizzi F, Nogues MV, Boix E
Eosinophil cationic protein aggregation: identification of an N-terminus amyloid prone region.
Biomacromolecules. 2010 Aug 9;11(8):1983-90. doi: 10.1021/bm100334u.
- PubMed ID
- 20690710 [ View in PubMed]
- Abstract
Eosinophil cationic protein (ECP) is an antimicrobial protein belonging to the superfamily of RNase A. ECP exhibits a broad spectrum of action against bacteria and, at higher concentrations, displays cytotoxic activity to eukaryotic cells. Recently, a powerful aggregation activity for lipid vesicles and for the gram-negative E. coli specie has also been related to the protein toxicity. Here we present the amyloid-like aggregation capacity of ECP. This is the first report of amyloid aggregation in a native nonengineered ribonuclease. The ECP aggregates are able to bind the amyloid-diagnostic dyes Thioflavin T and Congo Red and display a protofibril morphology when observed under electronic microscopy. We have also identified an N-terminus hydrophobic patch (residues 8-16) that is required for the amyloid aggregation process. A single substitution, I13A, breaks the aggregation prone sequence and abolishes the amyloid aggregation ability. Moreover, the corresponding R1N19 peptide is able to reproduce the protein amyloid-like aggregation behavior. The results may provide new clues on the protein antimicrobial mechanism and its toxicity to the host tissues in inflammation processes.