SpALF4: a newly identified anti-lipopolysaccharide factor from the mud crab Scylla paramamosain with broad spectrum antimicrobial activity.
SpALF4: a newly identified anti-lipopolysaccharide factor from the mud crab Scylla paramamosain with broad spectrum antimicrobial activity.
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DOI：
10.1016/j.fsi.2013.10.023
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发表时间：
2014-01
影响因子：
4.7
通讯作者：
Lei Zhu;Jiangfeng Lan;Yan-Qing Huang;Chao Zhang-;Jun-fang Zhou;W. Fang;Xiao-Juan Yao;Hao Wang;Xin-cang Li
中科院分区：
文献类型：
--
作者：
Lei Zhu;Jiangfeng Lan;Yan-Qing Huang;Chao Zhang-;Jun-fang Zhou;W. Fang;Xiao-Juan Yao;Hao Wang;Xin-cang Li
Anti-lipopolysaccharide factors (ALFs) are antimicrobial peptides with binding and neutralizing activities to lipopolysaccharide (LPS) in crustaceans. This study identified and characterized a novel ALF homolog (SpALF4) from the mud crabScylla paramamosain. The complete cDNA ofSpALF4had 756 bp with a 381 bp open reading frame encoding a protein with 126 aa. The deduced protein contained a signal peptide and a LPS-binding domain.SpALF4 shared the highest identity withPtALF5 at amino acid level but exhibited low similarity with most of other crustacean ALFs. Furthermore, different from the previously identified threeSpALF homologs and most of other ALFs,SpALF4 had a low isoelectric point (pI) for the mature peptide and the LPS-binding domain with the values of 6.93 and 6.74, respectively. These results indicate thatSpALF4 may be a unique ALF homolog with special biological function in the mud crab. Similar to the spatial structure of ALFPm3,SpALF4 contains three α-helices packed against a four-strand β-sheet, and an amphipathic loop formed by a disulphide bond between two conserved cysteine residues in LPS-binding domain.SpALF4, mainly distributed in hemocytes, could be upregulated by Vibrio harveyi, Staphylococcus aureus, or white spot syndrome virus. RecombinantSpALF4 could inhibit the growth of Gram-negative bacteria (V. harveyi, Vibrio anguillarum, Vibrio alginolyticus, Aeromonas hydrophila, Pseudomonas putida), Gram-positive bacteria (S. aureusand Bacillus megaterium), and a fungus Candida albicans to varying degrees. Further study showed that it could also bind to all the aforementioned microorganisms exceptS. aureus. These results demonstrate thatSpALF4 is a unique ALF homolog with potent antimicrobial activity against bacteria and fungi. This characteristic suggestsSpALF4 plays an essential function in immune defense against pathogen invasion in mud crab.
