Effect of buffer on heparin binding and sensing in competitive aqueous media
Effect of buffer on heparin binding and sensing in competitive aqueous media
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DOI：
10.1080/10610278.2016.1234711
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发表时间：
2017-01-01
影响因子：
3.3
通讯作者：
Smith, David K.
中科院分区：
文献类型：
--
作者：
Chan, Ching W.;Smith, David K.
虽然缓冲液对分子识别的特异性影响在生物科学中是已知的，但它们在超分子化学中仍然很少见。在三种常用的缓冲液（Tris-HCl、HEPES、磷酸盐，各10 mM）中研究了阳离子染料绿头鸭蓝（MalB）和聚阴离子肝素在NaCl水溶液（150 mM）中的结合。虽然MalB在每种缓冲液中具有非常相似的紫外-可见光谱，但在每种情况下对肝素的感觉反应不同。这可以归因于所形成的复合物的差异。在具有最少竞争性氯抗衡阴离子的Tris-HCl中，MalB表现出25 nm的蓝移，归因于染料在肝素上的强结合和聚集。在更有竞争力的HEPES中，含有磺酸根阴离子，MalB沿肝素沿着的结合较弱，聚集较少;蓝移仅为15 nm。在磷酸盐缓冲液中，MalB可以与缓冲液磷酸盐阴离子发生非常强烈的相互作用;尽管仍观察到肝素结合，但与染料聚集相关的蓝移仅为5 nm。因此，与MalB-肝素复合物的特定缓冲液相互作用介导宿主-客体结合和传感。在分子识别的研究中，缓冲液的选择必须谨慎--在研究静电结合时，我们要注意不要使用含磷酸盐和磺酸盐的缓冲液。[图片]
Although buffer-specific effects on molecular recognition are known in biological science, they remain rare in supramolecular chemistry. The binding between a cationic dye, mallard blue (MalB) and polyanionic heparin in aqueous NaCl (150mM) is studied in three commonly used buffers (Tris-HCl, HEPES, Phosphate, each 10mM). Although MalB has a very similar UV-visible spectrum in each buffer, the sensory response towards heparin was different in each case. This can be ascribed to differences in the complex formed. In Tris-HCl which has the least competitive chloride counter-anions, MalB exhibits a hypsochromic shift of 25nm, assigned to strong binding and aggregation of the dye on heparin. In more competitive HEPES, containing a sulfonate anion, there is weaker binding and less aggregation of MalB along the heparin; the hypsochromic shift is only 15nm. In phosphate buffer, MalB can interact quite strongly with buffer phosphate anions; although heparin binding is still observed, the hypsochromic shift associated with dye aggregation is only 5nm. As such, specific buffer interactions with the MalB-heparin complex mediate host-guest binding and sensing. Buffer choice must be made carefully in studies of molecular recognition - we would caution against using phosphate and sulfonate containing buffers when studying electrostatic binding.[GRAPHICS]