Identification of candidate antimicrobial peptides derived from abalone hemocyanin

Citation

Zhuang J, Coates C, Zhu H, Zhu P, Wu Z & Xie L (2015) Identification of candidate antimicrobial peptides derived from abalone hemocyanin. Developmental and Comparative Immunology, 49 (1), pp. 96-102. https://doi.org/10.1016/j.dci.2014.11.008

Abstract
Haemocyanins present in invertebrate hemolymph are multifunctional proteins, responsible for oxygen transport and contributing to innate immunity through phenoloxidase-like activity. In arthropods, haemocyanin has been identified as a source of broad-spectrum antimicrobial peptides during infection. Conversely, no haemocyanin-derived antimicrobial peptides have been reported for molluscs. The present study describes a putative antimicrobial region, termed haliotisin, located within the linking sequence between the α-helical domain and β-sheet domain of abalone (Haliotis tuberculata) haemocyanin functional unit E. A series of synthetic peptides based on overlapping fragments of the haliotisin region were tested for their bactericidal potential. Incubating Gram-positive and Gram-negative bacteria in the presence of certain haliotisin peptides, notably peptides 3-4-5 (DTFDYKKFGYRYDSLELEGRSISRIDELIQQRQEKDRTFAGFLLKGFGTSAS) led to reductions in microbial growth. Furthermore, transmission electron micrographs of haliotisin-treated bacteria revealed damages to the microbial cell wall. Data discussed here provides the first evidence to suggest that molluscan haemocyanin may act as a source of anti-infective peptides.

Keywords
Haemocyanin; Antimicrobial peptide; Mollusc; Haliotisin; Innate immunity; In silico

Journal
Developmental and Comparative Immunology: Volume 49, Issue 1