title: Novel members of glycoside hydrolase family 13 derived from environmental DNA.
abstract: Starch and pullulan-modifying enzymes of the alpha-amylase family (glycoside hydrolase family 13) have several industrial applications. To date, most of these enzymes have been derived from isolated organisms. To increase the number of members of this enzyme family, in particular of the thermophilic representatives, we have applied a consensus primer-based approach using DNA from enrichments from geothermal habitats. With this approach, we succeeded in isolating three new enzymes: a neopullulanase and two cyclodextrinases. Both cyclodextrinases displayed significant maltogenic amylase side activity, while one showed significant neopullulanase side activity. Specific motifs and domains that correlated with enzymatic activities were identified; e.g., the presence of the N domain was correlated with cyclodextrinase activity. The enzymes exhibited stability under thermophilic conditions and showed features appropriate for biotechnological applications.
authors.affiliation: Institut für Allgemeine Mikrobiologie, Christian-Albrechts-University Kiel, Am Botanischen Garten 1-9, DE-24118 Kiel, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Labes
authors.forename: Eva Nordberg
authors.initials: EN
authors.lastname: Karlsson
authors.forename: Olafur H
authors.initials: OH
authors.lastname: Fridjonsson
authors.forename: Pernilla
authors.initials: P
authors.lastname: Turner
authors.forename: Gudmundur O
authors.initials: GO
authors.lastname: Hreggvidson
authors.forename: Jakob K
authors.initials: JK
authors.lastname: Kristjansson
authors.forename: Olle
authors.initials: O
authors.lastname: Holst
authors.forename: Peter
authors.initials: P
authors.lastname: Schönheit
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics*; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011994:Recombinant Proteins; D006026:Glycoside Hydrolases; C058484:neopullulanase; C048745:cyclomaltodextrinase