||Rosa Rafael Diego1, Vergnes Agnes1, de Lorgeril Julien1, Goncalves Priscila2, Perazzolo Luciane Maria2, Saune Laure1, Romestand Bernard1, Fievet Julie1, Gueguen Yannick1, Bachere Evelyne1, Destoumieux-Garzon Delphine1
||1 : Univ Montpellier 2, Univ Montpellier 1, Inst Francais Rech Exploitat Mer, Inst Rech Dev,CNRS,UMR5119, Montpellier, France.
2 : Univ Fed Santa Catarina, Dept Cell Biol Embryol & Genet, Lab Immunol Appl Aquaculture, Florianopolis, SC, Brazil.
||Plos One (1932-6203) (Public Library Science), 2013-07 , Vol. 8 , N. 7 , P. -
|WOS© Times Cited
||Antilipopolysaccharide factors (ALFs) have been described as highly cationic polypeptides with a broad spectrum of potent antimicrobial activities. In addition, ALFs have been shown to recognize LPS, a major component of the Gram-negative bacteria cell wall, through conserved amino acid residues exposed in the four-stranded beta-sheet of their three dimensional structure. In penaeid shrimp, ALFs form a diverse family of antimicrobial peptides composed by three main variants, classified as ALF Groups A to C. Here, we identified a novel group of ALFs in shrimp (Group D ALFs), which corresponds to anionic polypeptides in which many residues of the LPS binding site are lacking. Both Group B (cationic) and Group D (anionic) shrimp ALFs were produced in a heterologous expression system. Group D ALFs were found to have impaired LPS-binding activities and only limited antimicrobial activity compared to Group B ALFs. Interestingly, all four ALF groups were shown to be simultaneously expressed in an individual shrimp and to follow different patterns of gene expression in response to a microbial infection. Group B was by far the more expressed of the ALF genes. From our results, nucleotide sequence variations in shrimp ALFs result in functional divergence, with significant differences in LPS-binding and antimicrobial activities. To our knowledge, this is the first functional characterization of the sequence diversity found in the ALF family.
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