1H NMR detection of immobilized water molecules within a strong distal hydrogen-bonding network of substrate-bound human heme oxygenase-1.
1H NMR detection of immobilized water molecules within a strong distal hydrogen-bonding network of substrate-bound human heme oxygenase-1.
复制标题
DOI：
10.1021/ja028108x
复制
发表时间：
2002-11
影响因子：
15
通讯作者：
R. Syvitski;Yiming Li;K. Auclair;P. Ortiz de Montellano;G. L. La Mar
中科院分区：
文献类型：
--
作者：
R. Syvitski;Yiming Li;K. Auclair;P. Ortiz de Montellano;G. L. La Mar
溶液1H NMR用于探测在氰化物抑制的、底物结合的人血红素加氧酶（hHO）复合物中血红素底物远端侧上的八个强氢键的供体质子的环境。它表明，显着的磁化传递从散装水信号的八个不稳定的质子不产生化学交换，但从直接的核Overhauser效应，由于这些不稳定的质子与“有序”的水分子的偶极相互作用。酶不稳定质子到水质子的距离估计约为3A。有人提出，强氢键网络的作用是使大量的水分子，既稳定活化的氢过氧物种和漏斗质子的活性位点。
Solution 1H NMR is used to probe the environments of the donor protons of eight strong hydrogen bonds on the distal side of the heme substrate in the cyanide-inhibited, substrate-bound complex of human heme oxygenase, hHO. It is demonstrated that significant magnetization transfer from the bulk water signal to the eight labile protons does not result from chemical exchange, but from direct nuclear Overhauser effect due to the dipolar interaction of these labile protons with "ordered" water molecules. The enzyme labile proton to water proton distances are estimated at approximately 3 A. It is proposed that the role of the strong hydrogen-bonding network is to immobilize numerous water molecules which both stabilize the activated hydroperoxy species and funnel protons to the active site.