Antimicrobial activity of histone1-derived peptides from large yellow croaker Larimichthys crocea

The function of histones is well-known in the folding and packaging of DNA, gene regulation, tumor formation, and apoptosis and they also have bactericidal properties. In the present study, two histone1-derived antimi-crobial peptides (LcH1-1 and LcH1-2) from Larimichthys crocea were described. The full-length cDNA of Lc-histione1 (LcH1) consisted of 1388 base pairs, including 588 bp open reading frame of, 5 ' UTR of 249 bp and 3 ' that of 551 bp. The molecular weight of LcH1 is 20,793.2 Da and the isoelectric point (pI) was 10.99. Two DNA-binding sites were predicted in LcH1. Tissue distribution analysis showed LcH1 presented a high expression pattern in gill, liver, and intestine. It also showed a time-dependent expression pattern after Cryptocaryon irritans infection. Maximum likelihood phylogenetic analysis showed that LcH1 had a relatively close relationship to homologous genes from Collichthys lucidus and Nibea albiora. Both LcH1-1 and LcH1-2 formed an amphipathic alpha-helix structure and displayed a broad antimicrobial spectrum against a variety of microbial strains. In addition, scanning electronic microscope (SEM) showed that the LcH1-1 and LcH1-2 peptides were prone to damage the integrity of the bacteria membrane. These results suggested that LcH1 may be involved in the immunoreaction of L. crocea under C. irritans challenge and that LcH1-derived antimicrobial peptides may provide a potential strategy for the control of parasitic and bacterial diseases.