Department of Chemistry, China Agricultural University, Beijing 100193, China.
J Photochem Photobiol B. 2012 Jan 5;106:53-60. doi: 10.1016/j.jphotobiol.2011.10.004. Epub 2011 Oct 30.
The purpose of the current work was to examine the complexation of a mammalian protein, hemoglobin (Hb) with a food additive hesperidin at physiological conditions. Molecular modeling, fluorescence, and circular dichroism (CD) methods were exploited to analyze the binding domain, affinity, and the effects of hesperidin conjugation on Hb spatial structure. From molecular modeling, central cavity of Hb was assigned to retain high-affinity for hesperidin, this corroborates the steady state fluorescence and hydrophobic ANS probe results. The association of hesperidin with Hb emerges fluorescence quenching via static type, this phenomenon display that the ground state complex formation with an affinity of 10(4)M(-1), and hypsochromic effect transpires. Additionally, the alterations of synchronous fluorescence, CD, and three-dimensional fluorescence suggest that the polypeptide chain of Hb partially folding after conjugation with hesperidin. The above data suggest that Hb plays a significant role in the plasma distribution and transportation of hesperidin and related dietary flavonoids.
本研究旨在考察哺乳动物蛋白血红蛋白(Hb)与食品添加剂橙皮苷在生理条件下的络合作用。利用分子模拟、荧光和圆二色性(CD)方法分析了橙皮苷与 Hb 的结合部位、亲和力以及橙皮苷结合对 Hb 空间结构的影响。分子模拟结果表明,Hb 的中心腔被分配为保留与橙皮苷的高亲和力,这与稳态荧光和疏水性 ANS 探针结果相符。橙皮苷与 Hb 的结合通过静态方式导致荧光猝灭,表明在 10(4)M(-1)的亲和力下形成了基态复合物,并发生了蓝移效应。此外,同步荧光、CD 和三维荧光的变化表明,橙皮苷结合后 Hb 的多肽链部分折叠。上述数据表明,Hb 在橙皮苷和相关膳食类黄酮在血浆中的分布和运输中起着重要作用。