Thieme R, Lay H, Oser A, Lehmann J, Wrissenberg S, Boos W
Eur J Biochem. 1986 Oct 1;160(1):83-91. doi: 10.1111/j.1432-1033.1986.tb09943.x.
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.
合成了具有两到六个（α1-4）连接的葡萄糖残基的麦芽低聚糖，其还原端带有以α或β糖苷键连接的3-叠氮基-1-甲氧基丁基。这些麦芽低聚糖类似物通过大肠杆菌中依赖麦芽糖结合蛋白的转运系统抑制麦芽糖摄取。在15 nM浓度下，麦芽糖转运半最大抑制浓度随类似物链长增加而降低，在α系列中四个葡萄糖残基链长后在40 μM达到平稳，在β系列中三个葡萄糖残基链长后在350 μM达到平稳。麦芽糖转运的抑制发生在周质麦芽糖结合蛋白水平。3-叠氮基-1-甲氧基丁基α-D-[3H]麦芽三糖苷与麦芽糖结合蛋白结合，解离常数为0.18 mM。在4 μM该底物存在下，对纯化的麦芽糖结合蛋白进行350 nm光照可使蛋白共价标记；1 mM麦芽糖可阻止标记。使用周质蛋白粗制品时，有两种蛋白被标记，即麦芽糖结合蛋白和α淀粉酶。因此，3-叠氮基-1-甲氧基丁基α-D-麦芽低聚糖是具有麦芽低聚糖结合位点的蛋白质的有效光亲和标记物。
