title: A new crystal form of a hyperthermophilic endocellulase.
abstract: The hyperthermophilic glycoside hydrolase family endocellulase 12 from the archaeon Pyrococcus furiosus (EGPf; Gene ID PF0854; EC 3.2.1.4) catalyzes the hydrolytic cleavage of the β-1,4-glucosidic linkage in β-glucan in lignocellulose biomass. A crystal of EGPf was previously prepared at pH 9.0 and its structure was determined at an atomic resolution of 1.07 Å. This article reports the crystallization of EGPf at the more physiologically relevant pH of 5.5. Structure determination showed that this new crystal form has the symmetry of space group C2. Two molecules of the enzyme are observed in the asymmetric unit. Crystal packing is weak at pH 5.5 owing to two flexible interfaces between symmetry-related molecules. Comparison of the EGPf structures obtained at pH 9.0 and pH 5.5 reveals a significant conformational difference at the active centre and in the surface loops. The interfaces in the vicinity of the flexible surface loops impact the quality of the EGPf crystal.
authors.affiliation: Biomass Refinery Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-hiroshima, Hiroshima 739-0046, Japan.
authors.forename: Misumi
authors.initials: M
authors.lastname: Kataoka
authors.affiliation: Biomass Refinery Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-hiroshima, Hiroshima 739-0046, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ishikawa
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D044602:Cellulases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008031:Lignin / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D020027:Pyrococcus furiosus / Q000737:chemistry* / Q000201:enzymology; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D047071:beta-Glucans / Q000737:chemistry / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D011994:Recombinant Proteins; D047071:beta-Glucans; C036909:lignocellulose; D008031:Lignin; D044602:Cellulases
keywords: Pyrococcus furiosus; endocellulase; hyperthermophile