title: Modification of a synthetic LPS-binding domain of anti-lipopolysaccharide factor from shrimp reveals strong structure-activity relationship in their antimicrobial characteristics.
abstract: Anti-lipopolysaccharide factor (ALF) is a small protein with broad-spectrum antimicrobial activities and certain antiviral property. Its putative lipopolysaccharide (LPS) binding domain was deduced to be important for its activities. However, there is still no report revealing how the structure of the LPS-binding domain affects its biological function until now. In the present study, we designed and synthesized a peptide corresponding to the LPS-binding domain of ALF from the Chinese shrimp (designated as FcALF-LBDc) and its structure-modified isoforms in order to analyze the relationship between its structure and antimicrobial activities. Results showed that FcALF-LBDc exhibited apparent antibacterial activities against both Gram-negative bacteria Escherichia coli and Vibrio anguillarum and Gram-positive bacteria Micrococcus luteus and Micrococcus lysodeikticus with MIC ranges of 32-64, 2-4, 1-2, and 32-64μM, respectively. The disulfide loop and the basic amino acids in the LPS-binding domain (LBD) of ALF played key roles in its antibacterial activities. In addition, FcALF-LBDc could reduce the propagation of white spot syndrome virus (WSSV) in vivo, and its lysine residue is indispensable for its antiviral property. This is the first attempt to testify the effects of the sequence features of the LPS-binding domain on its antimicrobial activities.
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Shuyue
authors.initials: S
authors.lastname: Guo
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
authors.forename: Shihao
authors.initials: S
authors.lastname: Li
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China. Electronic address: fhli@qdio.ac.cn.
authors.forename: Fuhua
authors.initials: F
authors.lastname: Li
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
authors.forename: Jianhai
authors.initials: J
authors.lastname: Xiang
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000276:immunology*; D008070:Lipopolysaccharides / Q000378:metabolism; D033541:Palaemonidae / Q000737:chemistry / Q000276:immunology* / Q000382:microbiology; D010455:Peptides / Q000276:immunology*; D013329:Structure-Activity Relationship; D046848:White spot syndrome virus 1 / Q000502:physiology
chemical_list: D060829:Arthropod Proteins; D008070:Lipopolysaccharides; D010455:Peptides
keywords: ALF; Antibacterial; Antiviral; LPS-binding domain; Shrimp