title: Cloning, expression and characterization of a new ι-carrageenase from marine bacterium, Cellulophaga sp.
abstract: The purpose of this study is to report a ι-carrageenase which degrades ι-carrageenan yielding neo-ι-carratetraose as the main product in the absence of NaCl. The gene for a new ι-carrageenase, CgiB_Ce, from Cellulophaga sp. QY3 was cloned and sequenced. It comprised an ORF of 1,386 bp encoding for a protein of 461 amino acid residues. From its sequence analysis, CgiB_Ce is a new member of GH family 82 and shared the highest identity of 32% in amino acids with ι-carrageenase CgiA2 from Zobellia galactanovorans indicating that it is a hitherto uncharacterized protein. The recombinant CgiB_Ce had maximum specific activity (1,870 U/mg) at 45 °C and pH 6.5. It was stable between pH 6.0-9.6 and below 40 °C. Although its activity was enhanced by NaCl, the enzyme was active in the absence of NaCl. CgiB_Ce is an endo-type ι-carrageenase that hydrolyzes β-1,4-linkages of ι-carrageenan, yielding neo-ι-carratetraose as the main product (more than 80% of the total product).
authors.affiliation: Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, Qingdao, 266003, China, masu277@gmail.com.
authors.forename: Su
authors.initials: S
authors.lastname: Ma
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Tan
authors.forename: Wen-Gong
authors.initials: WG
authors.lastname: Yu
authors.forename: Feng
authors.initials: F
authors.lastname: Han
mesh_terms: D059001:Aquatic Organisms / Q000201:enzymology* / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D002351:Carrageenan / Q000378:metabolism; D003001:Cloning, Molecular; D020536:Enzyme Activators / Q000378:metabolism; D004795:Enzyme Stability; D041965:Flavobacteriaceae / Q000201:enzymology* / Q000235:genetics*; D015870:Gene Expression; D006026:Glycoside Hydrolases / Q000235:genetics* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008969:Molecular Sequence Data; D010802:Phylogeny; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000378:metabolism; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D020536:Enzyme Activators; D011994:Recombinant Proteins; D012965:Sodium Chloride; D002351:Carrageenan; D006026:Glycoside Hydrolases; C019846:kappa-carrageenase protein, Alteromonadaceae