둥근성게(Strongylocentrotus nudus)의 생식선으로부터 항균성 펩타이드의 탐색 및 정제

Abstract

Recently, biologically materials derived from animals and plants have been studied in various ways, such as antimicrobial, antioxidant, and neurotransmitter materials. In particular, the marine ecosystem contains a lot of biologically materials such as toxic materials and antibacterial materials. The sea urchin (Strongylocentrotus nudus) is an invertebrate that relies on an innate immune response. In this innate immune response, antimicrobial peptides are considered to hold a crucial role. In this study, antimicrobial peptides were purified after screening for bioactive materials with the gonads of sea urchin. The gonad of sea urchin (1,037 g) was added to four volumes (w/v) of pre-heated distilled water containing 5% acetic acid and was boiled for 5 minutes. Subsequently, the extracted sample (75 ml) was separated into 4 fractions containing compounds that are eluted with D.W., 10%, 60% and 100% MeOH (in 0.1% TFA) using Sep-Pak C18 cartridges. The antimicrobial activity of the fractions was measured against B. subtillis KCTC1022 and 7 other strains by ultrasensitive radial diffusion assay (URDA). The material eluted with 10% MeOH (RM10) and 60% MeOH (RM60) showed good activity against B. subtillis KCTC1022 and 7 other strains. Therefore, RM60, which could contain highly active antimicrobial compounds, was used for further purification process by HPLC. Purification was perfomed using a column of Capcellpak C18 (4.6 x 250 mm). The purified materials were named strongylcentrotus nudus gonad 1 (SNG1) and strongylcentrotus nudus gonad 2 (SNG2) for convenience, respectively. The primary structures of SNG1 and SNG2 materials were partially determined by molecular weight analyzer and amino acid sequencer: SNG1; AKQVQTEDQVRQAILKTQ (2,109.1078 Da), SNG2; APVEK ERQIMQRKQKLVDHHGKMFGG (4,508.3087 Da. The partial primary sequences of the purified peptides were determined by Edman degradation, and homology search was conducted using the amino acid sequences of SNG1 & SNG2. As a result of comparing the sequence homology of SNG1 & SNG2, they showed a partial homology similar to that of the major yolk protein or vitellogenin in sea urchin. Further investigations into these purified peptides are ongoing.