title: A new group of glycoside hydrolase family 13 α-amylases with an aberrant catalytic triad.
abstract: α-Amylases are glycoside hydrolase enzymes that act on the α(1→4) glycosidic linkages in glycogen, starch, and related α-glucans, and are ubiquitously present in Nature. Most α-amylases have been classified in glycoside hydrolase family 13 with a typical (β/α)8-barrel containing two aspartic acid and one glutamic acid residue that play an essential role in catalysis. An atypical α-amylase (BmaN1) with only two of the three invariant catalytic residues present was isolated from Bacillus megaterium strain NL3, a bacterial isolate from a sea anemone of Kakaban landlocked marine lake, Derawan Island, Indonesia. In BmaN1 the third residue, the aspartic acid that acts as the transition state stabilizer, was replaced by a histidine. Three-dimensional structure modeling of the BmaN1 amino acid sequence confirmed the aberrant catalytic triad. Glucose and maltose were found as products of the action of the novel α-amylase on soluble starch, demonstrating that it is active in spite of the peculiar catalytic triad. This novel BmaN1 α-amylase is part of a group of α-amylases that all have this atypical catalytic triad, consisting of aspartic acid, glutamic acid and histidine. Phylogenetic analysis showed that this group of α-amylases comprises a new subfamily of the glycoside hydrolase family 13.
authors.affiliation: Biochemistry Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40132, Indonesia.|Aquatic Biotechnology and Bioproduct Engineering, Engineering and Technology institute Groningen (ENTEG), University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Fean D
authors.initials: FD
authors.lastname: Sarian
authors.affiliation: Laboratory of Protein Evolution, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, SK-84551 Bratislava, Slovakia.|Department of Biology, Faculty of Natural Sciences, University of SS. Cyril and Mehtodius, Nam. J. Herdu 2, SK-91701 Trnava, Slovakia.
authors.forename: Štefan
authors.initials: Š
authors.lastname: Janeček
authors.affiliation: X-Ray Crystallography, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors.forename: Tjaard
authors.initials: T
authors.lastname: Pijning
authors.affiliation: Biochemistry Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40132, Indonesia.
authors.lastname: Ihsanawati
authors.affiliation: Biochemistry Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40132, Indonesia.
authors.forename: Zeily
authors.initials: Z
authors.lastname: Nurachman
authors.affiliation: Department of Marine Science, Faculty of Fishery and Marine Science, Diponegoro University, Semarang 50275, Central Java, Indonesia.
authors.forename: Ocky K
authors.initials: OK
authors.lastname: Radjasa
authors.affiliation: Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
authors.forename: Lubbert
authors.initials: L
authors.lastname: Dijkhuizen
authors.affiliation: Biochemistry Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40132, Indonesia.
authors.forename: Dessy
authors.initials: D
authors.lastname: Natalia
authors.affiliation: Aquatic Biotechnology and Bioproduct Engineering, Engineering and Technology institute Groningen (ENTEG), University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Marc J E C
authors.initials: MJ
authors.lastname: van der Maarel
mesh_terms: D001410:Bacillus megaterium / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D002384:Catalysis; D013213:Starch / Q000737:chemistry* / Q000378:metabolism; D000516:alpha-Amylases / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D013213:Starch; D000516:alpha-Amylases