title: A trimeric and thermostable lichenase from B. pumilus US570 strain: Biochemical and molecular characterization.
abstract: New β-1,3;1,4-glucanase (GluUS570) was purified from a newly isolated Bacillus pumilus US570 strain. The enzyme was active in a wide range of pH and temperature and displayed a great thermostability with a half-life of 30min at 80°C. The enzyme was demonstrated to be a lichenase since it was only active toward glucan containing β-1,3;1,4- linkages. The analysis of the enzyme in native and denaturing conditions suggests that it has a trimeric form (75kDa). This is the first report on the purification and characterization of a bacterial lichenase with a trimeric structure. β-1,3;1,4-glucanase encoding gene was amplified, cloned and sequenced showing an open reading frame of 732bp encoding 243 amino acids. The GluUS570 enzyme showed 97% homology with glucanase from Bacillus lichenoformis. The 3D model of GluUS570 in trimeric form was generated and showed that a region named R2 was involved in the oligomerization of the enzyme.
authors.affiliation: Laboratoire de Biotechnologie Microbienne et d'Ingénierie des Enzymes (LBMIE), Centre de Biotechnologie de Sfax (CBS), Université de Sfax, Route de Sidi Mansour Km 6, BP "1177" 3018 Sfax, Tunisia.
authors.forename: Fatma
authors.initials: F
authors.lastname: Elgharbi
authors.affiliation: Laboratoire de Biotechnologie Microbienne et d'Ingénierie des Enzymes (LBMIE), Centre de Biotechnologie de Sfax (CBS), Université de Sfax, Route de Sidi Mansour Km 6, BP "1177" 3018 Sfax, Tunisia.
authors.forename: Hajer
authors.initials: H
authors.lastname: Ben Hlima
authors.affiliation: Laboratoire de Biotechnologie Microbienne et d'Ingénierie des Enzymes (LBMIE), Centre de Biotechnologie de Sfax (CBS), Université de Sfax, Route de Sidi Mansour Km 6, BP "1177" 3018 Sfax, Tunisia.
authors.forename: Rihab
authors.initials: R
authors.lastname: Ameri
authors.affiliation: Laboratoire de Biotechnologie Microbienne et d'Ingénierie des Enzymes (LBMIE), Centre de Biotechnologie de Sfax (CBS), Université de Sfax, Route de Sidi Mansour Km 6, BP "1177" 3018 Sfax, Tunisia.
authors.forename: Samir
authors.initials: S
authors.lastname: Bejar
authors.affiliation: Laboratoire de Biotechnologie Microbienne et d'Ingénierie des Enzymes (LBMIE), Centre de Biotechnologie de Sfax (CBS), Université de Sfax, Route de Sidi Mansour Km 6, BP "1177" 3018 Sfax, Tunisia. Electronic address: aidahmida@yahoo.fr.
authors.forename: Aïda
authors.initials: A
authors.lastname: Hmida-Sayari
mesh_terms: D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology*; D004795:Enzyme Stability; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008670:Metals / Q000494:pharmacology; D008958:Models, Molecular; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D008670:Metals; D006026:Glycoside Hydrolases; C028020:licheninase
keywords: 3D model; Thermostable lichenase; Trimeric form