title: 3-Azi-1-methoxybutyl D-maltooligosaccharides specifically bind to the maltose/maltooligosaccharide-binding protein of Escherichia coli and can be used as photoaffinity labels.
abstract: Maltooligosaccharides with two to six (alpha 1-4)-linked glucose residues, carrying at their reducing end a 3-azi-1-methoxybutyl group in either alpha or in beta glycosidic linkage, were synthesized. These maltooligosaccharide analogues inhibit maltose uptake via the maltose-binding-protein-dependent transport system in Escherichia coli. The concentration of half-maximal inhibition of maltose transport, at 15 nM concentration, decreases with increasing chain length of the analogue, levelling off at 40 microM after a chain length of four glucose residues in the alpha series and at 350 microM after a chain length of three glucose residues in the beta series. The inhibition of maltose transport occurs at the level of the periplasmic maltose-binding protein. 3-Azi-1-methoxybutyl alpha-D-[3H]maltotrioside was bound by the maltose-binding protein with a Kd of 0.18 mM. Irradiation at 350 nm of purified maltose-binding protein in the presence of 4 microM of this substrate labeled the protein covalently; labeling was prevented by 1 mM maltose. Using a crude preparation of periplasmic proteins two proteins were labeled, the maltose-binding protein and alpha-amylase. Thus, 3-azi-1-methoxybutyl alpha-D-maltooligosaccharides are potent photoaffinity labels for proteins with maltooligosaccharides-binding sites.
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000345:Affinity Labels / Q000138:chemical synthesis*; D001386:Azides / Q000138:chemical synthesis* / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D008320:Maltose / Q000378:metabolism; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000378:metabolism; D033902:Periplasmic Binding Proteins; D010777:Photochemistry; D011485:Protein Binding
chemical_list: D018528:ATP-Binding Cassette Transporters; D000345:Affinity Labels; D001386:Azides; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C461619:MalE protein, E coli; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D009844:Oligosaccharides; D033902:Periplasmic Binding Proteins; C461599:maltose transport system, E coli; D008320:Maltose