title: Thermotoga neapolitana bglB gene, upstream of lamA, encodes a highly thermostable beta-glucosidase that is a laminaribiase.
abstract: The gene for thermostable 1,3-beta-glucosidase BglB was cloned from the chromosome of Thermotoga neapolitana and its primary sequence was determined. The purified recombinant beta-glucosidase B had a monomer molecular mass of 81 kDa in accordance with the amino acid sequence predicted from the nucleotide sequence of clone pTT51. It was a member of glycosylhydrolase family 3 and belonged to enzyme class EC 3.2.1.21. beta-Glucosidase B had a specific activity of 255 U mg-1 on 4-nitrophenyl(PNP)-beta-glucoside at the optima of pH (5.5) and temperature (90 degrees C), and K(m) values of 0.1, 10 and 50 mM for PNP-beta-glucoside, laminaribiose and cellobiose, respectively. The gene bglB was located immediately upstream of the laminarinase gene lamA. Both genes were transcribed from the same DNA strand and were not separated by a palindromic transcription terminator. The two purified enzymes 1,3-beta-glucosidase BglB (laminaribiase) and 1,3-beta-glucanase LamA (laminarinase) were together capable of completely degrading laminarin to glucose.
authors.affiliation: Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq. 46, 123 182 Moscow, Russia.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Zverlov
authors.affiliation: Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq. 46, 123 182 Moscow, Russia.
authors.forename: Ilia Y
authors.initials: IY
authors.lastname: Volkov
authors.affiliation: Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq. 46, 123 182 Moscow, Russia.
authors.forename: Tatjana V
authors.initials: TV
authors.lastname: Velikodvorskaya
authors.affiliation: Institute for Microbiology, Technical University of München, Arcisstr. 21, D-80290 München, Germany.
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Schwarz
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004187:Disaccharides / Q000378:metabolism*; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics*; D004693:Glucan Endo-1,3-beta-D-Glucosidase / Q000235:genetics / Q000378:metabolism; D006089:Gram-Negative Anaerobic Bacteria / Q000201:enzymology / Q000235:genetics*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011993:Recombinant Fusion Proteins; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D001617:beta-Glucosidase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D004187:Disaccharides; D011993:Recombinant Fusion Proteins; C014637:laminaribiose; D001617:beta-Glucosidase; D004693:Glucan Endo-1,3-beta-D-Glucosidase