title: Purification and characterization of a proline-rich antibacterial peptide, with sequence similarity to bactenecin-7, from the haemocytes of the shore crab, Carcinus maenas.
abstract: Antibacterial peptides are important for non-specific host defence in many animals. They have been extensively characterized from mammals, amphibians, insects and chelicerates but have not so far been found in crustaceans. Here we report the presence of several constitutive antibacterial proteins, active against both gram-positive and gram-negative bacteria, in the haemocytes of the shore crab, Carcinus maenas. These proteins have molecular masses of > 70 kDa, approximately 45 kDa, approximately 14 kDa and 6.5 kDa. The 6.5 kDa peptide has been purified to homogeneity by Sep Pak C18 extraction, gel filtration and reverse-phase HPLC. Partial N-terminal sequence analysis further shows that it is proline rich and shares more than 60% identity in a 28-amino-acid overlap with the mature form of bactenecin 7, an antimicrobial peptide from bovine neutrophils which belongs to the cathelicidin family of mammalian peptide antibiotics.
authors.affiliation: Gatty Marine Laboratory, School of Biological and Medical Sciences, University of St Andrews, Scotland.
authors.forename: D
authors.initials: D
authors.lastname: Schnapp
authors.forename: G D
authors.initials: GD
authors.lastname: Kemp
authors.forename: V J
authors.initials: VJ
authors.lastname: Smith
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D003386:Brachyura / Q000737:chemistry* / Q000235:genetics; D002417:Cattle; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D006434:Hemocytes / Q000737:chemistry*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009504:Neutrophils / Q000737:chemistry; D010456:Peptides, Cyclic / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D011392:Proline / Q000032:analysis; D017386:Sequence Homology, Amino Acid
chemical_list: D000900:Anti-Bacterial Agents; D010456:Peptides, Cyclic; C056454:bactenecin; D011392:Proline