Expression and characterization of a bifunctional alginate lyase named Al163 from the Antarctic bacterium Pseudoalteromonas sp. NJ-21  

作　　者：XIE Maisheng LI Jiang HE Peiqing LIN Xuezheng 谢买胜;李江;何培青;林学政(Key Laboratory of Marine Bioactive Substances,The First Institute of Oceanography,State Oceanic Administration（SOA）Qingdao 266061,China;Key Laboratory of Marine Natural Products of Qingdao,Qingdao 266061,China)

机构地区：[1]Key Laboratory of Marine Bioactive Substances, The First Institute of Oceanography, State Oceanic Administration (SOA), Qingdao 266061, China [2]Key Laboratory of Marine Natural Products of Qingdao, Qingdao 266061, China

出　　处：《Journal of Oceanology and Limnology》2018年第4期1304-1314,共11页海洋湖沼学报（英文）

基　　金：Supported by the Public Science and Technology Research Funds Project of Ocean(No.201505026-4);the Chinese Polar Environment Comprehensive Investigation&Assessment Programs(No.CHINARE2016-01-05);the Basic Scientific Research Funds of First Institute of Oceanography,State Oceanic Administration(SOA)(No.2014T09);the Qingdao Applied Basic Research Project(No.14-2-4-14-jch)

摘　　要：In this study, an endolytic alginate lyase, named Al163, was identified, cloned, and characterized from the Antarctic bacterium Pseudoalteromonas sp. NJ-21. Comparative sequence analysis showed that the predicted amino acid sequence encoded by al163 belongs to the polysaccharide lyase 6(PL-6) family and has a molecular mass of about 80 kDa. Recombinant enzyme was purified by Ni-Sepharose affinity chromatography. Recombinant Al163 exhibited maximum activity(258 U/mg) at pH 7.0 and 40℃, and thermal stability assays showed retention of almost 90% activity after incubation at 30℃ for 30 min. Al163 activity was stimulated by Cd^(2+), Ca^(2+), Fe^(3+), and Mn^(2+), but inhibited by Cu^(2+), Si^(2+), Fe^(2+), and Ni^(2+). Thin-layer chromatographic analysis indicated that Al163 degraded sodium alginate, poly M, and poly G, generating disaccharides and trisaccharides as the final products. Only a few bacterial strains that produce a bifunctional alginate lyase have been reported. Our results indicate that recombinant Al163 exhibits broad substrate specificity and its products exhibit low degrees of polymerization. Both properties imply high potential for use of the enzyme in several industrial fields, including cosmetics and pharmaceuticals, based on the high demand for biologically active oligosaccharides.In this study, an endolytic alginate lyase, named Al163, was identified, cloned, and characterized from the Antarctic bacterium Pseudoalteromonas sp. NJ-21. Comparative sequence analysis showed that the predicted amino acid sequence encoded by al163 belongs to the polysaccharide lyase 6（PL-6） family and has a molecular mass of about 80 kDa. Recombinant enzyme was purified by Ni-Sepharose affinity chromatography. Recombinant Al163 exhibited maximum activity（258 U/mg） at pH 7.0 and 40℃, and thermal stability assays showed retention of almost 90% activity after incubation at 30℃ for 30 min. Al163 activity was stimulated by Cd^2＋, Ca^2＋, Fe^3＋, and Mn^2＋, but inhibited by Cu^2＋, Si^2＋, Fe^2＋, and Ni^2＋. Thin-layer chromatographic analysis indicated that Al163 degraded sodium alginate, poly M, and poly G, generating disaccharides and trisaccharides as the final products. Only a few bacterial strains that produce a bifunctional alginate lyase have been reported. Our results indicate that recombinant Al163 exhibits broad substrate specificity and its products exhibit low degrees of polymerization. Both properties imply high potential for use of the enzyme in several industrial fields, including cosmetics and pharmaceuticals, based on the high demand for biologically active oligosaccharides.

关 键 词：Pseudoalteromonas sp. alginate lyase PL-6 family 

分 类 号：P728.2[天文地球—海洋科学] Q939.1[生物学—微生物学]