title: Atomic resolution of the crystal structure of the hyperthermophilic family 12 endocellulase and stabilizing role of the DxDxDG calcium-binding motif in Pyrococcus furiosus.
abstract: Hyperthermophilic glycoside hydrolase family 12 endocellulase (EGPf) from the archaeon Pyrococcus furiosus catalyzes the hydrolytic cleavage of β-1,4-glucosidic linkage in β-glucan cellulose. A truncated EGPf (EGPfΔN30) mutant lacking the proline and hydroxyl-residue rich region at the N terminus was constructed, and its crystal structure was resolved at an atomic resolution of 1.07 Å. Our results indicate that the structure of EGPf, which consists of a β-jelly roll, exhibits structural similarity with the endocellulase of Thermotoga maritima. Additionally, we further determined that the thermostability of EGPf is maintained in part by the binding of Ca²⁺ in a DxDxDG Ca²⁺-binding motif, atypical of most archaeal proteins.
authors.affiliation: National Institute of Advanced Industrial Science and Technology, Biomass Technology Research Center, 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-0046, Japan.
authors.forename: Han-Woo
authors.initials: HW
authors.lastname: Kim
authors.forename: Misumi
authors.initials: M
authors.lastname: Kataoka
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ishikawa
mesh_terms: D020816:Amino Acid Motifs; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002152:Calorimetry, Differential Scanning; D020134:Catalytic Domain; D044602:Cellulases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D018389:Codon, Nonsense; D018360:Crystallography, X-Ray; D004795:Enzyme Stability; D006358:Hot Temperature; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008024:Ligands; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D020027:Pyrococcus furiosus / Q000201:enzymology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D047071:beta-Glucans / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D018389:Codon, Nonsense; D007527:Isoenzymes; D008024:Ligands; D010446:Peptide Fragments; D011994:Recombinant Proteins; D047071:beta-Glucans; D002482:Cellulose; D044602:Cellulases; D002118:Calcium