title: Enzymatic properties and nucleotide and amino acid sequences of a thermostable beta-agarase from the novel marine isolate, JAMB-A94.
abstract: A gene, agaA, for a novel beta-agarase from the marine bacterium JAMB-A94 was cloned and sequenced. The 16S rDNA of the isolate had the closest match, of only 94.8% homology, with that from Microbulbifer salipaludis JCM11542(T). The agaA gene encoded a protein with a calculated molecular mass of 48,203 Da. The deduced amino acid sequence showed 37-66% identity to those of known agarases in glycoside hydrolase family 16. A carbohydrate-binding module-like amino acid sequence was found in the C-terminal region. The recombinant enzyme was hyper-produced extracellularly when Bacillus subtilis was used as a host. The purified enzyme was an endo-type beta-agarase, yielding neoagarotetraose as the main final product. It was very thermostable up to 60 degrees C. The optimal pH and temperature for activity were around 7.0 and 55 degrees C respectively. The activity was not inhibited by EDTA (up to 100 mM) and sodium dodecyl sulfate (up to 30 mM).
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Ohta
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Nogi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Miyazaki
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Li
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hatada
authors.forename: Susumu
authors.initials: S
authors.lastname: Ito
authors.forename: Koki
authors.initials: K
authors.lastname: Horikoshi
mesh_terms: D034241:Alteromonadaceae / Q000201:enzymology* / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D004795:Enzyme Stability; D006026:Glycoside Hydrolases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D006358:Hot Temperature; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010802:Phylogeny; D012685:Sepharose / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D012685:Sepharose; D006026:Glycoside Hydrolases; C019624:agarase