Synthesis of FimH receptor-active manno-oligosaccharides by reverse hydrolysis using alpha-mannosidases from Penicillium citrinum, Aspergillus phoenicis and almond.
Recombinant Penicillium citrinum alpha-1,2-mannosidase, expressed in Aspergillus oryzae, was employed to carry out regioselective synthesis of alpha- d-mannopyranosyl-(1-->2)- d-mannose. Yields (w/w) of 16.68% disaccharide, 3.07% trisaccharide and 0.48% tetrasaccharide were obtained, with alpha1-->2 linkages present at 98.5% of the total linkages formed. Non-specific alpha-mannosidase from almond was highly efficient in reverse hydrolysis and oligosaccharide yields of 45-50% were achieved. The products of the almond mannosidase were a mixture of disaccharides (30.75%, w/w), trisaccharides (12.26%, w/w) and tetrasaccharides (1.89%, w/w) with 1-->2, 1-->3 and 1-->6 isomers. alpha-1,2-linkage specific mannosidase from P. citrinum and alpha-1,6-linkage-specific mannosidase from Aspergillus phoenicis were used in combination to hydrolyse the respective linkages from the mixture of isomers, resulting in alpha- d-mannopyranosyl-(1-->3)- d-mannose in 86.4% purity. The synthesised oligosaccharides can potentially inhibit the adhesion of pathogens by acting as "decoys" of receptors of type-1 fimbriae carried by enterobacteria.
Maitin
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School of Food Biosciences, The University of Reading, Whiteknights, PO Box 226, RG6 6AP, Reading, UK.
Athanasopoulos
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Rastall
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RA
D018830:Adhesins, Escherichia coli / Q000378:metabolism; D001230:Aspergillus / Q000201:enzymology / Q000235:genetics; D001422:Bacterial Adhesion / Q000187:drug effects; D002236:Carbohydrate Conformation; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D004795:Enzyme Stability; D036781:Fimbriae Proteins / Q000378:metabolism; D005800:Genes, Fungal; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008361:Mannosidases / Q000378:metabolism; D008362:Mannosides / Q000096:biosynthesis*; D009844:Oligosaccharides / Q000032:analysis / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D010407:Penicillium / Q000201:enzymology / Q000235:genetics; D027861:Prunus / Q000201:enzymology; D011971:Receptors, Immunologic / Q000378:metabolism; D013696:Temperature; D043323:alpha-Mannosidase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D018830:Adhesins, Escherichia coli; D008362:Mannosides; D009844:Oligosaccharides; D011971:Receptors, Immunologic; C058769:fimH protein, E coli; C076610:fimbriae receptor, type 1; D036781:Fimbriae Proteins; D008361:Mannosidases; C046090:mannosyl-oligosaccharide 1,2-alpha-mannosidase; D043323:alpha-Mannosidase