title: First crenarchaeal chitinase found in Sulfolobus tokodaii.
abstract: This is the first description of a functional chitinase gene within the crenarchaeotes. Here we report of the heterologues expression of the ORF BAB65950 from Sulfolobus tokodaii in E. coli. The resulting protein degraded chitin and was hence classified as chitinase (EC 3.2.4.14). The protein characterization revealed a specific activity of 75 mU/mg using colloidal chitin as substrate. The optimal activity of the enzyme was measured at pH 2.5 and 70°C, respectively. A dimeric enzyme configuration is proposed. According to amino acid sequence similarities chitinases are attributed to the two glycoside hydrolase families 18 and 19. The derived amino acid sequence of the S. tokodaii gene differed from sequences of these two glycoside hydrolase families. However, within a phylogenetic tree of protein sequences, the crenarchaeal sequence of S. tokodaii clustered in close proximity to members of the glycoside hydrolase family 18.
authors.affiliation: Kieler Wirkstoff-Zentrum am IFM-GEOMAR, Am Kiel Kanal 44, D-24106 Kiel, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Staufenberger
authors.forename: Johannes F
authors.initials: JF
authors.lastname: Imhoff
authors.forename: Antje
authors.initials: A
authors.lastname: Labes
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002688:Chitinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004795:Enzyme Stability; D008969:Molecular Sequence Data; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D016944:Sulfolobus / Q000737:chemistry / Q000145:classification / Q000201:enzymology* / Q000235:genetics
chemical_list: D019843:Archaeal Proteins; D002688:Chitinases