title: First characterization of extremely halophilic 2-deoxy-D-ribose-5-phosphate aldolase.
abstract: 2-Deoxy-d-ribose-5-phosphate aldolase (DERA) catalyzes the aldol reaction between two aldehydes and is thought to be a potential biocatalyst for the production of a variety of stereo-specific materials. A gene encoding DERA from the extreme halophilic archaeon, Haloarcula japonica, was overexpressed in Escherichia coli. The gene product was successfully purified, using procedures based on the protein's halophilicity, and characterized. The expressed enzyme was stable in a buffer containing 2 M NaCl and exhibited high thermostability, retaining more than 90% of its activity after heating at 70 °C for 10 min. The enzyme was also tolerant to high concentrations of organic solvents, such as acetonitrile and dimethylsulfoxide. Moreover, H. japonica DERA was highly resistant to a high concentration of acetaldehyde and retained about 35% of its initial activity after 5-h' exposure to 300 mM acetaldehyde at 25 °C, the conditions under which E. coli DERA is completely inactivated. The enzyme exhibited much higher activity at 25 °C than the previously characterized hyperthermophilic DERAs (Sakuraba et al., 2007). Our results suggest that the extremely halophilic DERA has high potential to serve as a biocatalyst in organic syntheses. This is the first description of the biochemical characterization of a halophilic DERA.
authors.affiliation: Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0795, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ohshida
authors.affiliation: Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0795, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Hayashi
authors.affiliation: Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui, 910-8507, Japan.
authors.forename: Takenori
authors.initials: T
authors.lastname: Satomura
authors.affiliation: Division of Environmental Symbiosis Studies, Graduate School of Integrated Arts and Sciences, Tokushima University, 1-1 Minamijosanjima-cho, Tokushima, Tokushima, 770-8502, Japan.
authors.forename: Ryushi
authors.initials: R
authors.lastname: Kawakami
authors.affiliation: Department of Biomedical Engineering, Faculty of Engineering, Osaka Institute of Technology, 5-16-1 Omiya, Asahi-ku, Osaka, 535-8585, Japan.
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Ohshima
authors.affiliation: Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0795, Japan. Electronic address: sakuraba@ag.kagawa-u.ac.jp.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Sakuraba
mesh_terms: D000446:Aldehyde-Lyases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D019843:Archaeal Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D019613:Haloarcula / Q000201:enzymology / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D012965:Sodium Chloride / Q000737:chemistry*
chemical_list: D019843:Archaeal Proteins; D011994:Recombinant Proteins; D012965:Sodium Chloride; D000446:Aldehyde-Lyases
keywords: 2-Deoxy-d-ribose-5-phosphate aldolase; Aldehyde; Archaea; Haloarcula japonica; Halophile; Organic solvent