LAUSR

BACKGROUND In this study, an ι-carrageenase gene, Car1293 was obtained from the genome of Microbulbifer sp. YNDZ01, which was isolated from the surface of macroalgae, Indonesia. Up to now, there are few studies on ι-carrageenase and the anti-inflammatory activity of ι-carrageenan oligosaccharides (CGOS). To enhance our perspective on ι-carrageenase and ι-carrageen oligosaccharides, the genes sequence, protein structure, enzymatic properties, enzymatic digestion products and its anti-inflammatory activity were investigated. RESULTS The gene length of Car1293 is 2,589 bp, encoding an enzyme with 862 amino acids, which shares 34% similarity with any previously reported ι-carrageenase. Spatial structure of Car1293 is consisted of many α-helices with a β-fold binding module located at its terminu, and eight binding sites were found in the binding module based on the result of docking with CGOS-DP4 ligand. The optimum temperature and pH for the activity of recombinant Car1293 toward ι-carrageenan were 50°C and 6.0, respectively. The hydrolysates of Car1293 are mainly degree of polymerization (DP) 8 with minor products having DP2, DP4 and DP6. The enzymatic hydrolysates CGOS-DP8 showed prominent anti-inflammatory activity that was greater than that of the positive control L-monomethylarginine in lipopolysaccharide-induced RAW264.7 macrophages; it inhibited NO production, and significantly inhibited tumor necrosis factor-α and interleukin-6 secretion. CONCLUSION The ι-carrageenase sequence encoded by Car1293 is novel and can hydrolyze carrageenan into CGOS-DP8 that has a significant anti-inflammatory effect. This study fills a gap in the research on the biological activity of oligosaccharides in ι-carrageenan and provides promising data for the development of natural anti-inflammatory agent. This article is protected by copyright. All rights reserved.