title: Cloning, Expression, and Biochemical Characterization of a Novel Acidic GH16 β-Agarase, AgaJ11, from Gayadomonas joobiniege G7.
abstract: A novel β-agarase AgaJ11 belonging to the glycoside hydrolase (GH) 16 family was identified from an agar-degrading bacterium Gayadomonas joobiniege G7. AgaJ11 was composed of 317 amino acids (35 kDa), including a 26-amino acid signal peptide, and had the highest similarity (44 % identity) to a putative β-agarase from an agarolytic marine bacterium Agarivorans albus MKT 106. The agarase activity of purified AgaJ11 was confirmed by zymogram analysis. The optimum pH and temperature for AgaJ11 activity were determined to be 4.5 and 40 °C, respectively. Notably, AgaJ11 is an acidic β-agarase that was active only at a narrow pH range from 4 to 5, and less than 30 % of its enzymatic activity was retained at other pH conditions. The Kmand Vmaxof AgaJ11 for agarose were 21.42 mg/ml and 25 U/mg, respectively. AgaJ11 did not require metal ions for its activity, but severe inhibition by several metal ions was observed. Thin layer chromatography and agarose-liquefying analyses revealed that AgaJ11 is an endo-type β-agarase that hydrolyzes agarose into neoagarohexaose, neoagarotetraose, and neoagarobiose. Therefore, this study shows that AgaJ11 from G. joobiniege G7 is a novel GH16 β-agarase with an acidic enzymatic feature that may be useful for industrial applications.
authors.affiliation: Department of Biological Sciences, Myongji University, Yongin, Gyeonggido, 449-728, Republic of Korea.
authors.forename: Subin
authors.initials: S
authors.lastname: Jung
authors.affiliation: Department of Biological Sciences, Myongji University, Yongin, Gyeonggido, 449-728, Republic of Korea.
authors.forename: Byeong-Chul
authors.initials: BC
authors.lastname: Jeong
authors.affiliation: Department of Biological Sciences, Myongji University, Yongin, Gyeonggido, 449-728, Republic of Korea.
authors.forename: Soon-Kwang
authors.initials: SK
authors.lastname: Hong
authors.affiliation: Department of Biological Sciences, Myongji University, Yongin, Gyeonggido, 449-728, Republic of Korea. crlee@mju.ac.kr.
authors.forename: Chang-Ro
authors.initials: CR
authors.lastname: Lee
mesh_terms: D034241:Alteromonadaceae / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D003001:Cloning, Molecular; D015870:Gene Expression; D006026:Glycoside Hydrolases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D006026:Glycoside Hydrolases; C019624:agarase
keywords: Agar; GH16; Gayadomonas joobiniege; β-agarase