Crystal structure of endo‐1, 4‐β‐glucanase from Eisenia fetida. (1st October 2013)

• Record Type: Journal Article
• Authors: Arimori, Takao; Ito, Akihiro; Nakazawa, Masami; Ueda, Mitsuhiro; Tamada, Taro
• Is Part Of: Journal of synchrotron radiation. Volume 20:Part 6(2013)
• Page Start: 884
• Page End: 889
• Publication Date: 2013-10-01
• Subjects: Synchrotron radiation -- Periodicals; Free electron lasers -- Periodicals; 539.73505
• DOI: 10.1107/S0909049513021110
• Languages: English
• ISSNs: 0909-0495

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The saccharification process is essential for bioethanol production from woody biomass including celluloses. Cold‐adapted cellulase, which has sufficient activity at low temperature (<293 K), is capable of reducing heating costs during the saccharification process and is suitable for simultaneous saccharification and fermentation. Endo‐1, 4‐β‐glucanase from the earthworm <italic>Eisenia fetida</italic> (EF‐EG2) belonging to glycoside hydrolase family 9 has been shown to have the highest activity at 313 K, and also retained a comparatively high activity at 283 K. The recombinant EF‐EG2 was purified expressed in <italic>Pichia pastoris, </italic> and then grew needle‐shaped crystals with dimensions of 0.02 × 0.02 × 1 mm. The crystals belonged to the space group <italic>P</italic>3<sub>2</sub>21 with unit‐cell parameters of <italic>a</italic> = <italic>b</italic> = 136 Å, <italic>c</italic> = 55.0 Å. The final model of EF‐EG2, including 435 residues, two ions, seven crystallization reagents and 696 waters, was refined to a crystallographic <italic>R</italic>‐factor of 14.7% (free <italic>R</italic>‐factor of 16.8%) to 1.5 Å resolution. The overall structure of EF‐EG2 has an (α/α)<sub>6</sub> barrel fold which contains a putative active‐site cleft and a negatively charged surface. This structural information helps us understand the catalytic and cold adaptation mechanisms of EF‐EG2.</p> </abstract>