title: A new high-alkaline alginate lyase from a deep-sea bacterium Agarivorans sp.
abstract: A high-alkaline, salt-activated alginate lyase is produced by Agarivorans sp. JAM-A1m from a deep-sea sediment off Cape Nomamisaki on Kyushu Island, Japan. Purified to homogeneity, as judged by SDS-PAGE, the enzyme (A1m) had a molecular mass of approximately 31 kDa. The optimal pH was around 10 in glycine-NaOH buffer, and the activity was increased to 1.8 times by adding 0.2 M NaCl. However, when the optimal pH in the presence of 0.2 M NaCl was shifted to pH 9.0, the activity was more than 10 times compared with that at pH 9 in the absence of NaCl. A1m showed the optimal temperature at around 30 degrees C and was stable to incubation between pH 6 and 9. The enzyme degraded favorably mannuronate-guluronate and guluronate-rich fragments in alginate. Shotgun cloning and sequencing of the gene for A1m revealed a 930-bp open reading frame, which encoded a mature enzyme of 289 amino acids (32,295 Da) belonging to polysaccharide lyase family 7. The deduced amino acid sequence showed the highest similarity to that of a Klebsiella enzyme, with only 54% identity.
authors.affiliation: Extremobiosphere Research Center, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima, Yokosuka 237-0061, Japan. kobayashit@jamstec.go.jp
authors.forename: Tohru
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Uchimura
authors.forename: Masayuki
authors.initials: M
authors.lastname: Miyazaki
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Nogi
authors.forename: Koki
authors.initials: K
authors.lastname: Horikoshi
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008386:Marine Biology; D016366:Open Reading Frames; D011133:Polysaccharide-Lyases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D020560:Proteobacteria / Q000201:enzymology* / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014871:Water Microbiology
chemical_list: D017931:DNA Primers; D012336:RNA, Ribosomal, 16S; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase