Discovery and Characterization of a Thermostable and Highly Halotolerant GH5 Cellulase from an Icelandic Hot Spring Isolate

Dimitra Zarafeta; Dimitrios Kissas; Christopher Sayer; Sóley R Gudbergsdottir; Efthymios Ladoukakis; Michail N Isupov; Aristotelis Chatziioannou; Xu Peng; Jennifer A Littlechild; Georgios Skretas; Fragiskos N Kolisis

doi:10.1371/journal.pone.0146454

Discovery and Characterization of a Thermostable and Highly Halotolerant GH5 Cellulase from an Icelandic Hot Spring Isolate

PLoS One. 2016 Jan 7;11(1):e0146454. doi: 10.1371/journal.pone.0146454. eCollection 2016.

Affiliations

¹ Institute of Biology, Medicinal Chemistry & Biotechnology, National Hellenic Research Foundation, Athens, Greece.
² Laboratory of Biotechnology, School of Chemical Engineering, National Technical University of Athens, Athens, Greece.
³ Henry Wellcome Building for Biocatalysis, Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
⁴ Danish Archaea Centre, Department of Biology, Copenhagen University, Copenhagen, Denmark.

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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bacterial Proteins / chemistry
Bacterial Proteins / genetics*
Catalytic Domain
Cellulase / chemistry
Cellulase / genetics*
Cellulose / chemistry
Chlorides / chemistry
Crystallography, X-Ray
Enzyme Stability
Hot Springs / microbiology
Hot Temperature
Hydrogen-Ion Concentration
Iceland
Kinetics
Models, Molecular
Salt Tolerance
Substrate Specificity
Thermoanaerobacter / enzymology*
Thermoanaerobacter / genetics

Substances

Bacterial Proteins
Chlorides
Cellulose
Cellulase

Associated data

PDB/5FIP

Grants and funding

This work has been carried out in the framework of the HotZyme Project (http://hotzyme.com, grant agreement no. 265933) financed by the European Union 7th Framework Programme FP7/2007-2013, an EU FP7 Collaborative programme. MNI would like to thank the BBSRC funded ERA-IB grant BB/L002035/1 and the University of Exeter for their support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.