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Novel cathelicidin‐derived antimicrobial peptides from Equus asinus
Author(s) -
Lu Zekuan,
Wang Yipeng,
Zhai Lei,
Che Qiaolin,
Wang Hui,
Du Shuyuan,
Wang Duo,
Feng Feifei,
Liu Jingze,
Lai Ren,
Yu Haining
Publication year - 2010
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2010.07648.x
Subject(s) - cathelicidin , microbiology and biotechnology , antimicrobial , staphylococcus aureus , antimicrobial peptides , bacteria , biology , chemistry , minimum inhibitory concentration , genetics
In the present study, EA‐CATH1 and EA‐CATH2 were identified from a constructed lung cDNA library of donkey ( Equus asinus ) as members of cathelicidin‐derived antimicrobial peptides, using a nested PCR‐based cloning strategy. Composed of 25 and 26 residues, respectively, EA‐CATH1 and EA‐CATH2 are smaller than most other cathelicidins and have no sequence homology to other cathelicidins identified to date. Chemically synthesized EA‐CATH1 exerted potent antimicrobial activity against most of the 32 strains of bacteria and fungi tested, especially the clinically isolated drug‐resistant strains, and minimal inhibitory concentration values against Gram‐positive bacteria were mostly in the range of 0.3–2.4 μg·mL −1 . EA‐CATH1 showed an extraordinary serum stability and no haemolytic activity against human erythrocytes in a dose up to 20 μg·mL −1 . CD spectra showed that EA‐CATH1 mainly adopts an α‐helical conformation in a 50% trifluoroethanol/water solution, but a random coil in aqueous solution. Scanning electron microscope observations of Staphylococcus aureus (ATCC2592) treated with EA‐CATH1 demonstrated that EA‐CATH could cause rapid disruption of the bacterial membrane, and in turn lead to cell lysis. This might explain the much faster killing kinetics of EA‐CATH1 than conventional antibiotics revealed by killing kinetics data. In the presence of CaCl 2 , EA‐CATH1 exerted haemagglutination activity, which might potentiate an inhibition against the bacterial polyprotein interaction with the host erythrocyte surface, thereby possibly restricting bacterial colonization and spread.