title: Characterization of two glycoside hydrolase family 36 α-galactosidases: novel transglycosylation activity, lead-zinc tolerance, alkaline and multiple pH optima, and low-temperature activity.
abstract: Two α-galactosidases, AgaAJB07 from Mesorhizobium and AgaAHJG4 from Streptomyces, were expressed in Escherichia coli. Recombinant AgaAJB07 showed a 2.9-fold and 22.6-fold increase in kcat with a concomitant increase of 2.3-fold and 16.3-fold in Km in the presence of 0.5mM ZnSO4 and 30.0mM Pb(CH3COO)2, respectively. Recombinant AgaAHJG4 showed apparent optimal activity at pH 8.0 in McIlvaine or Tris-HCl buffer and 9.5 in glycine-NaOH or HCl-borax-NaOH buffer, retention of 23.6% and 43.2% activity when assayed at 10 and 20°C, respectively, and a half-life of approximately 2min at 50°C. The activation energies for p-nitrophenyl-α-d-galactopyranoside hydrolysis by AgaAJB07 and AgaAHJG4 were 71.9±0.8 and 48.2±2.0kJmol(-1), respectively. Both AgaAJB07 and AgaAHJG4 exhibited transglycosylation activity, but they required different acceptors and produced different compounds. Furthermore, potential factors for alkaline and multiple pH optima and low-temperature adaptations of AgaAHJG4 were presumed.
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China; College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan, Kunming 650500, People's Republic of China; Key Laboratory of Enzyme Engineering, Yunnan Normal University, Kunming 650500, People's Republic of China.
authors.forename: Junpei
authors.initials: J
authors.lastname: Zhou
authors.affiliation: College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Lu
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China; College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan, Kunming 650500, People's Republic of China; Key Laboratory of Enzyme Engineering, Yunnan Normal University, Kunming 650500, People's Republic of China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.affiliation: College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China.
authors.forename: Yiyan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China; College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan, Kunming 650500, People's Republic of China; Key Laboratory of Enzyme Engineering, Yunnan Normal University, Kunming 650500, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China; College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan, Kunming 650500, People's Republic of China; Key Laboratory of Enzyme Engineering, Yunnan Normal University, Kunming 650500, People's Republic of China.
authors.forename: Junjun
authors.initials: J
authors.lastname: Li
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China; College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan, Kunming 650500, People's Republic of China; Key Laboratory of Enzyme Engineering, Yunnan Normal University, Kunming 650500, People's Republic of China.
authors.forename: Xianghua
authors.initials: X
authors.lastname: Tang
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China; College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan, Kunming 650500, People's Republic of China; Key Laboratory of Enzyme Engineering, Yunnan Normal University, Kunming 650500, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Xu
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China; College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan, Kunming 650500, People's Republic of China; Key Laboratory of Enzyme Engineering, Yunnan Normal University, Kunming 650500, People's Republic of China.
authors.forename: Junmei
authors.initials: J
authors.lastname: Ding
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, People's Republic of China; College of Life Sciences, Yunnan Normal University, Kunming 650500, People's Republic of China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan, Kunming 650500, People's Republic of China; Key Laboratory of Enzyme Engineering, Yunnan Normal University, Kunming 650500, People's Republic of China. Electronic address: huangzunxi@163.com.
authors.forename: Zunxi
authors.initials: Z
authors.lastname: Huang
mesh_terms: D005690:Galactose; D006027:Glycosides / Q000737:chemistry*; D006868:Hydrolysis; D007854:Lead; D013696:Temperature; D015032:Zinc; D000519:alpha-Galactosidase / Q000737:chemistry*
chemical_list: D006027:Glycosides; D007854:Lead; D000519:alpha-Galactosidase; D015032:Zinc; D005690:Galactose
keywords: Lead–zinc tolerance; Low-temperature activity; Transglycosylation; pH optimum; α-Galactosidase