Glucan synthesis in the genus Lactobacillus: isolation and characterization of glucansucrase genes, enzymes and glucan products from six different strains

• Published in: Microbiology (Society for General Microbiology) Vol. 150; no. 11; pp. 3681 - 3690
• Main Authors: Kralj, S, van Geel-Schutten, G. H, Dondorff, M. M. G, Kirsanovs, S, van der Maarel, M. J. E. C, Dijkhuizen, L
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.11.2004; Society for General Microbiology
• Subjects: Amino Acid Motifs; Bacterial plant pathogens; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Binding Sites; Biological and medical sciences; Catalytic Domain; Cloning, Molecular; DNA, Bacterial - chemistry; DNA, Bacterial - isolation & purification; Escherichia coli - genetics; Escherichia coli - metabolism; Fundamental and applied biological sciences. Psychology; Genes, Bacterial; Glucans - biosynthesis; Glucans - chemistry; Glucosyltransferases - genetics; Glucosyltransferases - metabolism; Glycosyltransferases - genetics; Glycosyltransferases - metabolism; Growth, nutrition, metabolism, transports, enzymes. Molecular biology; Lactobacillus; Lactobacillus - enzymology; Lactobacillus - genetics; Lactobacillus - metabolism; Lactobacillus fermentum; Lactobacillus reuteri; Lactobacillus sakei; Leuconostoc; Microbiology; Miscellaneous; Molecular Sequence Data; Mycology; Phylogeny; Phytopathology. Animal pests. Plant and forest protection; Protein Sorting Signals; Protein Structure, Tertiary; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Repetitive Sequences, Amino Acid; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Streptococcus; Sucrase - genetics; Sucrase - metabolism; Dextransucrase; Lactic acid bacteria; Gene product; Variable region; Glycosyltransferases; Leuconostoc; Glucan; Gene; Blood substitute; Streptococcal infection; Bacteria; Lactobacillaceae; Micrococcales; Lactobacillus fermentum; Nucleotide sequence; Enzyme; Transferases; Protein; Strain; Infection; Dextran; Streptococcaceae; Streptococcus; Bacteriosis; Isolation; Hexosyltransferases; Detection
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.27321-0

1 Centre for Carbohydrate Bioengineering (CCB), TNO-University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands 2 Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kerklaan 30, 9751 NN, Haren, The Netherlands 3 Innovative Ingredients and Products Department, TNO Nutrition and Food Research, Utrechtseweg 48, 3704 HE, Zeist, The Netherlands 4 Innovative Ingredients and Products Department, TNO Nutrition and Food Research, Rouaanstraat 27, 9723 CC, Groningen, The Netherlands Correspondence L. Dijkhuizen L.Dijkhuizen{at}biol.rug.nl Members of the genera Streptococcus and Leuconostoc synthesize various -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 -(1 4) linkages together with -(1 6) and -(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 -(1 6)- and -(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. Abbreviations: GBD, glucan-binding domain; GTF, glucosyltransferase; HPSEC, high performance size exclusion chromatography; iPCR, inverse PCR The GenBank/EMBL/DDBJ accession numbers for the sequences of the Lactobacillus gtf genes gtf180 , gtfML1 , gtf33 , gtfKg3 , gtfKg15 and gtfB and their flanking regions are AY697430 , AY697431 , AY697432 , AY697433 , AY697434 and AY697435 .