Novel oligosaccharides synthesized from sucrose donor and cellobiose acceptor by alternansucrase.
Cellobiose was tested as acceptor in the reaction catalyzed by alternansucrase (EC 2.4.1.140) from Leuconostoc mesenteroides NRRL B-23192. The oligosaccharides synthesized were compared to those obtained with dextransucrase from L. mesenteroides NRRL B-512F. With alternansucrase and dextransucrase, overall oligosaccharide synthesis yield reached 30 and 14%, respectively, showing that alternansucrase is more efficient than dextransucrase for cellobiose glucosylation. Interestingly, alternansucrase produced a series of oligosaccharides from cellobiose. Their structure was determined by mass spectrometry and [13C-1H] NMR spectroscopy. Two trisaccharides are first produced: alpha-D-glucopyranosyl-(1-->2)-[beta-D-glucopyranosyl-(1-->4)]-D-glucopyranose (compound A) and alpha-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-(1-->4)-D-glucopyranose (compound B). Then, compound B can in turn be glucosylated leading to the synthesis of a tetrasaccharide with an additional alpha-(1-->6) linkage at the non-reducing end (compound D). The presence of the alpha-(1-->3) linkage occurred only in the pentasaccharides (compounds C1 and C2) formed from tetrasaccharide D. Compounds B, C1, C2 and D were never described before. They were produced efficiently only by alternansucrase. Their presence emphasizes the difference existing in the acceptor reaction selectivity of the various glucansucrases.
Argüello Morales
M A
MA
Department de Génie Biochimique et Alimentaire, Centre de Bioingénierie, Gilbert Durand, UMR CNRS 5504, UMR INRA 792, INSA, Toulouse, France.
Remaud-Simeon
M
M
Willemot
R M
RM
Vignon
M R
MR
Monsan
P
P
D002240:Carbohydrate Sequence; D002475:Cellobiose / Q000378:metabolism*; D005964:Glucosyltransferases / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000378:metabolism*; D016695:Glycosyltransferases; D007934:Leuconostoc / Q000201:enzymology; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009844:Oligosaccharides / Q000096:biosynthesis*; D013395:Sucrose / Q000378:metabolism*
D009844:Oligosaccharides; D002475:Cellobiose; D013395:Sucrose; D016695:Glycosyltransferases; D005964:Glucosyltransferases; C033837:alternansucrase; C020025:dextransucrase; D006026:Glycoside Hydrolases