Partial purification of lectin from hemolymph of Penaeus Merguiensis with antibacterial activity and bacterial clearance activity

Abstract

Lectins play relevant role in humoral defenses of invertebrates. The hemolymph of banana prawn, Penaeus merguiensis contains a lectains a lectin (PML). In an attempt to identify the lectin subunits and responsive proteins in banana prawn after infected with Vibrio harveyi, lectin was purified by affinity chromatography on mucin-CNBr-activated Sepharose 4B and by gel filtration chromatography on Sephacryl S-200. The native molecular mass of PML was estimated to be 112 kDa and consisted of 30.09 (PML1) and 28.01 kDa (PML2) subunits by SDS-PAGE. Isoelectric point of PML was 5.23. The internal amino acid sequence of purified lectin from P. merguiensis by gel filtration was analyzed by 2-D gel electrophoresis and LC-MS/MS and then compared with nrFasta database which it was identified to be DAELLLLR DAEALEVGR and DTDVTTVRSR. The antibacterial activity of gel filtration purified lectin on Vibrio spp. Was higher than that of affinity purified lectin. Protein profile of affinity purified lectin after the prawns were infected with V. haruyi by SDS-PAGE and 2-D gel electrophoresis demonstrated that the lectin expression responded to the bacterial infection. These results indicated that lectin has antibacterial activity and involved in shrimp immune responses.