title: Discovery and Characterization of a Thermostable and Highly Halotolerant GH5 Cellulase from an Icelandic Hot Spring Isolate.
abstract: With the ultimate goal of identifying robust cellulases for industrial biocatalytic conversions, we have isolated and characterized a new thermostable and very halotolerant GH5 cellulase. This new enzyme, termed CelDZ1, was identified by bioinformatic analysis from the genome of a polysaccharide-enrichment culture isolate, initiated from material collected from an Icelandic hot spring. Biochemical characterization of CelDZ1 revealed that it is a glycoside hydrolase with optimal activity at 70°C and pH 5.0 that exhibits good thermostability, high halotolerance at near-saturating salt concentrations, and resistance towards metal ions and other denaturing agents. X-ray crystallography of the new enzyme showed that CelDZ1 is the first reported cellulase structure that lacks the defined sugar-binding 2 subsite and revealed structural features which provide potential explanations of its biochemical characteristics.
authors.affiliation: Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece.|Laboratory of Biotechnology, School of Chemical Engineering, National Technical University of Athens, Athens, Greece.
authors.forename: Dimitra
authors.initials: D
authors.lastname: Zarafeta
authors.affiliation: Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece.|Laboratory of Biotechnology, School of Chemical Engineering, National Technical University of Athens, Athens, Greece.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Kissas
authors.affiliation: Henry Wellcome Building for Biocatalysis, Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Sayer
authors.affiliation: Danish Archaea Centre, Department of Biology, Copenhagen University, Copenhagen, Denmark.
authors.forename: Sóley R
authors.initials: SR
authors.lastname: Gudbergsdottir
authors.affiliation: Laboratory of Biotechnology, School of Chemical Engineering, National Technical University of Athens, Athens, Greece.
authors.forename: Efthymios
authors.initials: E
authors.lastname: Ladoukakis
authors.affiliation: Henry Wellcome Building for Biocatalysis, Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors.forename: Michail N
authors.initials: MN
authors.lastname: Isupov
authors.affiliation: Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece.
authors.forename: Aristotelis
authors.initials: A
authors.lastname: Chatziioannou
authors.affiliation: Danish Archaea Centre, Department of Biology, Copenhagen University, Copenhagen, Denmark.
authors.forename: Xu
authors.initials: X
authors.lastname: Peng
authors.affiliation: Henry Wellcome Building for Biocatalysis, Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Littlechild
authors.affiliation: Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece.
authors.forename: Georgios
authors.initials: G
authors.lastname: Skretas
authors.affiliation: Laboratory of Biotechnology, School of Chemical Engineering, National Technical University of Athens, Athens, Greece.
authors.forename: Fragiskos N
authors.initials: FN
authors.lastname: Kolisis
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D020134:Catalytic Domain; D002480:Cellulase / Q000737:chemistry / Q000235:genetics*; D002482:Cellulose / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D018360:Crystallography, X-Ray; D004795:Enzyme Stability; D045482:Hot Springs / Q000382:microbiology; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007055:Iceland; D007700:Kinetics; D008958:Models, Molecular; D055049:Salt Tolerance; D013379:Substrate Specificity; D046968:Thermoanaerobacter / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D002712:Chlorides; D002482:Cellulose; D002480:Cellulase