Saccharide receptor achieves concentration dependent mannoside selectivity through two distinct cooperative binding pathways
Saccharide receptor achieves concentration dependent mannoside selectivity through two distinct cooperative binding pathways
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DOI：
10.1039/c2sc20873c
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发表时间：
2013-01-01
期刊：
影响因子：
8.4
通讯作者：
Braunschweig, Adam B.
中科院分区：
文献类型：
--
作者：
Rieth, Stephen;Miner, Matthew R.;Braunschweig, Adam B.
四足受体1依赖于结构的灵活性，以揭示新的糖识别结合模式，并实现独特的吡喃糖苷结合亲和力和浓度依赖性的选择性。通过H-1 NMR滴定法在CDCl 3中测量细胞表面聚糖中常见的1至8种吡喃糖苷之间的缔合常数K（a）s，揭示了对α-和β-辛基吡喃甘露糖苷（α-Man和β-Man）的偏好。尽管大多数研究的吡喃糖苷-α/β-辛基吡喃葡萄糖苷（α/β-Glc）、α/β-辛基吡喃半乳糖苷（α/β-Gal）和α/β-辛基N-乙酰氨基葡萄糖苷（α/β-GlcNAc）-在25 ℃下以1：1的化学计量结合1，但β-Man仅形成2：1的受体-吡喃糖苷复合物。或者，在过量的吡喃糖苷中，1以1：2的受体：吡喃糖苷化学计量结合α-和β-Man，具有高度的正协同性（α-和β-Man的K-2/K-1分别类似于13.7和7.6）和高达16.8：1的α-Man：α-Gal的选择性。此外，这种偏好作为吡喃糖苷浓度的函数而变化，在低浓度下有利于β-Glc（
Tetrapodal receptor 1 relies upon structural flexibility to reveal new binding modes for saccharide recognition and to achieve unique pyranoside binding affinity and concentration dependent selectivity. The association constants, K(a)s, between 1 and eight pyranosides commonly found in cell surface glycans were measured in CDCl3 by H-1 NMR titrations, revealing a preference for alpha- and beta-octyl mannopyranosides (alpha-Man and beta-Man). Whereas most of the pyranosides studied - alpha/beta-octyl glucopyranoside (alpha/beta-Glc), alpha/beta-octyl galactopyranoside (alpha/beta-Gal), and alpha/beta-octyl N-acetylglucosaminopyranoside (alpha/beta-GlcNAc) - bind 1 in a 1 : 1 stoichiometry at 25 degrees C, beta-Man exclusively forms a 2 : 1 receptor-pyranoside complex. Alternatively, in an excess of pyranoside, 1 binds alpha- and beta-Man in a 1 : 2 receptor : pyranoside stoichiometry with a high degree of positive cooperativity (K-2/K-1 similar to 13.7 and 7.6 for alpha- and beta-Man respectively) and selectivities as high as 16.8 : 1 alpha-Man : alpha-Gal. Moreover, this preference changes as a function of pyranoside concentration, favoring beta-Glc at low concentration (