Onchorhyncin III: a potent antimicrobial peptide derived from the non-histone chromosomal protein H6 of rainbow trout, Oncorhynchus mykiss

A 6.7 kDa antimicrobial peptide was isolated from trout skin secretions using acid extraction followed by cation-exchange chromatography, C-18, solid-phase extraction, and C-18 reversed-phase HPLC. The molecular mass of this peptide, which is tentatively named oncorhyncin III, is 6671 Da, as determi...

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Bibliographic Details
Published in:Biochemical Journal
Main Authors: Fernandes, Jorge, Saint, N, Kemp, Graham Duncan, Smith, Valerie Jane
Format: Article in Journal/Newspaper
Language:English
Published: 2003
Subjects:
antimicrobial peptide
historic
mucosal immunity
oncorhyncin III
teleost
trout
HUMAN CDNA SEQUENCE
HISTONE H2A
MULTIGENE FAMILY
SKIN SECRETIONS
ATLANTIC SALMON
MECHANISM
MEMBRANE
BINDING
HMG-14
TESTIS
Atlantic salmon
Online Access:https://risweb.st-andrews.ac.uk/portal/en/researchoutput/onchorhyncin-iii-a-potent-antimicrobial-peptide-derived-from-the-nonhistone-chromosomal-protein-h6-of-rainbow-trout-oncorhynchus-mykiss(43355219-b6fc-4d1d-b319-8b0d64493abc).html
https://doi.org/10.1042/BJ20030259
http://www.scopus.com/inward/record.url?scp=0041364483&partnerID=8YFLogxK
Description
Summary:A 6.7 kDa antimicrobial peptide was isolated from trout skin secretions using acid extraction followed by cation-exchange chromatography, C-18, solid-phase extraction, and C-18 reversed-phase HPLC. The molecular mass of this peptide, which is tentatively named oncorhyncin III, is 6671 Da, as determined by matrix-assisted laser-desorption ionization MS. N-terminal amino acid sequencing revealed that the first 13 residues of oncorhyncin III are identical with those of the non-histone chromosomal protein H6 from rainbow trout. Hence these data combined with the MS results indicate that oncorhyncin III is likely to be a cleavage product of the non-histone chromosomal protein H6 (residues 1-66) and that it probably contains two methylated residues or one double methylation. The purified peptide exhibits potent antibacterial activity against both Gram-positive and Gram-negative bacteria, with minimal inhibitory concentrations in the submicromolar range. The peptide is sensitive to NaCl, and displays no haemolytic activity towards trout erythrocytes at concentrations below 1 muM. Scanning electron microscopy revealed that oncorhyncin III does not cause direct disruption of bacterial cells. Reconstitution of the peptide in planar lipid bilayers strongly disturbs the membranes, but does not induce the formation of stable ion channels. Taken together, these results support the hypothesis that oncorhyncin III plays a role in mucosal innate host defence.

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