title: Glucan synthesis in the genus Lactobacillus: isolation and characterization of glucansucrase genes, enzymes and glucan products from six different strains.
abstract: Members of the genera Streptococcus and Leuconostoc synthesize various alpha-glucans (dextran, alternan and mutan). In Lactobacillus, until now, the only glucosyltransferase (GTF) enzyme that has been characterized is gtfA of Lactobacillus reuteri 121, the first GTF enzyme synthesizing a glucan (reuteran) that contains mainly alpha-(1-->4) linkages together with alpha-(1-->6) and alpha-(1-->4,6) linkages. Recently, partial sequences of glucansucrase genes were detected in other members of the genus Lactobacillus. This paper reports, for the first time, isolation and characterization of dextransucrase and mutansucrase genes and enzymes from various Lactobacillus species and the characterization of the glucan products synthesized, which mainly have alpha-(1-->6)- and alpha-(1-->3)-glucosidic linkages. The four GTF enzymes characterized from three different Lb. reuteri strains are highly similar at the amino acid level, and consequently their protein structures are very alike. Interestingly, these four Lb. reuteri GTFs have relatively large N-terminal variable regions, containing RDV repeats, and relatively short putative glucan-binding domains with conserved and less-conserved YG-repeating units. The three other GTF enzymes, isolated from Lactobacillus sakei, Lactobacillus fermentum and Lactobacillus parabuchneri, contain smaller variable regions and larger putative glucan-binding domains compared to the Lb. reuteri GTF enzymes.
authors.affiliation: Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN, Haren, The Netherlands.|Centre for Carbohydrate Bioengineering (CCB), TNO-University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Kralj
authors.affiliation: Innovative Ingredients and Products Department, TNO Nutrition and Food Research, Utrechtseweg 48, 3704 HE, Zeist, The Netherlands.|Centre for Carbohydrate Bioengineering (CCB), TNO-University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
authors.forename: G H
authors.initials: GH
authors.lastname: van Geel-Schutten
authors.affiliation: Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN, Haren, The Netherlands.|Centre for Carbohydrate Bioengineering (CCB), TNO-University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
authors.forename: M M G
authors.initials: MMG
authors.lastname: Dondorff
authors.affiliation: Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN, Haren, The Netherlands.|Centre for Carbohydrate Bioengineering (CCB), TNO-University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Kirsanovs
authors.affiliation: Innovative Ingredients and Products Department, TNO Nutrition and Food Research, Rouaanstraat 27, 9723 CC, Groningen, The Netherlands.|Centre for Carbohydrate Bioengineering (CCB), TNO-University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
authors.forename: M J E C
authors.initials: MJEC
authors.lastname: van der Maarel
authors.affiliation: Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN, Haren, The Netherlands.|Centre for Carbohydrate Bioengineering (CCB), TNO-University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: Dijkhuizen
mesh_terms: D020816:Amino Acid Motifs; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D020134:Catalytic Domain; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D005936:Glucans / Q000096:biosynthesis* / Q000737:chemistry*; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D016695:Glycosyltransferases / Q000235:genetics* / Q000378:metabolism; D007778:Lactobacillus / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020449:Repetitive Sequences, Amino Acid; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013393:Sucrase / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D005936:Glucans; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D016695:Glycosyltransferases; D005964:Glucosyltransferases; C033837:alternansucrase; C020025:dextransucrase; D013393:Sucrase