Chemoenzymatic synthesis of 6 omega-S-alpha-D-glucopyranosyl-6 omega-thiomaltooligosaccharides: their binding to Aspergillus niger glucoamylase G1 and its starch-binding domain.
A coupling reaction of cyclodextrin glucosyltransferase (CGTase) with glucose and 6-deoxy-6-iodo-cyclomaltoheptaose (1), in the presence of glucoamylase, followed by acetylation, led to a convenient synthesis of acetylated 6III-deoxy-6III-iodo-maltotriose (2) and 6IV-deoxy-6IV-iodomaltotraose (3). Nucleophilic displacement of the iodine atom of these protected maltotriose and maltotetraose analogs by the activated form of 2,3,4,6-tetra-O-acetyl-1-S- acetyl-1-thio-alpha-D-glucose (4) afforded peracetylated 6III-S-alpha-D-glucopyranosyl-6III-thiomaltotriose (5) and 6IV-S-alpha-D-glucopyranosyl-6IV-thiomaltotetraose (6) in high yield. The interaction of OH-free tetra- and penta-saccharides (7 and 8) with both glucoamylase G1 from Aspergillus niger as well as its isolated starch-binding domain fragment were studied by UV difference spectroscopy. It was found that the starch-binding domain has higher affinity for 7 and 8 than for maltotetraose and maltopentaose.
Apparu
C
C
Centre de Recherches sur les Macromolécules Végétales (CERMAV-CNRS), Grenoble, France.
Driguez
H
H
Williamson
G
G
Svensson
B
B
D001234:Aspergillus niger / Q000201:enzymology*; D001665:Binding Sites; D002240:Carbohydrate Sequence; D003505:Cyclodextrins / Q000378:metabolism; D005087:Glucan 1,4-alpha-Glucosidase / Q000737:chemistry / Q000378:metabolism*; D005964:Glucosyltransferases / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008320:Maltose / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000378:metabolism; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000378:metabolism; D013213:Starch / Q000378:metabolism*; D013865:Thioglycosides / Q000138:chemical synthesis* / Q000378:metabolism*; D014312:Trisaccharides / Q000138:chemical synthesis / Q000378:metabolism
D003505:Cyclodextrins; D009844:Oligosaccharides; D013865:Thioglycosides; D014312:Trisaccharides; C008317:maltotriose; D008320:Maltose; D013213:Starch; C009819:maltotetraose; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase; D005087:Glucan 1,4-alpha-Glucosidase