A New κ-Carrageenase Cgk S from Marine Bacterium Shewanella sp. Kz7  

作　　者：WANG Linna LI Shangyong ZHANG Shilong LI Jiejing YU Wengong GONG Qianhong 

机构地区：[1]Key Laboratory of Marine Drugs of Chinese Ministry of Education, Shandong Provincial Key Laboratory of Glycoscience & Glycotechnology, School of Medicine and Pharmacy, Ocean University of China

出　　处：《Journal of Ocean University of China》2015年第4期759-763,共5页中国海洋大学学报（英文版）

基　　金：supported by the Key Technologies Research and Development Program of China(2013BA B01B02);National Science Foundation of China(310707 12);Special Fund for Marine Scientific Research in the Public Interest(201005024 and 201105027);National Hightech R&D Program of China(2011AA09070304)

摘　　要：A new κ-carrageenase gene cgkS was cloned from marine bacterium Shewanella sp. Kz7 by using degenerate and site-finding PCR. The gene was comprised of an open reading frame of 1224bp, encoding 407 amino acid residues, with a signal peptide of 24 residues. Based on the deduced amino acid sequence, the κ-carrageenase CgkS was classified into the Glycoside Hy- drolase family 16. The cgkS gene was expressed in Escherichia coli, and the recombinant enzyme was purified to homogeneity with a specific activity of 716.8 U mg-1 and a yield of 69%. Recombinant CgkS was most active at 45 ℃ and pH 8.0. It was stable at pH 6.0-9.0 and below 30℃. The enzyme did not require NaCl for activity, although its activity was enhanced by NaCI. CgkS degraded κ-carrageenan in an endo-fashion releasing tetrasaccharides and disaccharides as main hydrolysis products.A new κ-carrageenase gene cgk S was cloned from marine bacterium Shewanella sp. Kz7 by using degenerate and site-finding PCR. The gene was comprised of an open reading frame of 1224 bp, encoding 407 amino acid residues, with a signal peptide of 24 residues. Based on the deduced amino acid sequence, the κ-carrageenase Cgk S was classified into the Glycoside Hydrolase family 16. The cgk S gene was expressed in Escherichia coli, and the recombinant enzyme was purified to homogeneity with a specific activity of 716.8 U mg-1 and a yield of 69%. Recombinant Cgk S was most active at 45℃ and p H 8.0. It was stable at p H 6.0–9.0 and below 30℃. The enzyme did not require Na Cl for activity, although its activity was enhanced by Na Cl. Cgk S degraded κ-carrageenan in an endo-fashion releasing tetrasaccharides and disaccharides as main hydrolysis products.

关 键 词：Κ-CARRAGEENAN CLONING CHARACTERIZATION OLIGOSACCHARIDE SHEWANELLA 

分 类 号：S917.1[农业科学—水产科学]