1H NMR study of the effect of variable ligand on heme oxygenase electronic and molecular structure.
1H NMR study of the effect of variable ligand on heme oxygenase electronic and molecular structure.
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DOI：
10.1016/j.jinorgbio.2008.08.012
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发表时间：
2009-01
影响因子：
3.9
通讯作者：
Mar, Gerd N. La
中科院分区：
文献类型：
--
作者：
Ma, Li-Hua;Liu, Yangzhong;Zhang, Xuhong;Yoshida, Tadashi;Mar, Gerd N. La
血红素加氧酶对原血红素进行立体特异性分解代谢，产生铁、CO 和胆绿素。生理氧复合物的不稳定性使得需要使用模型配体，其中氰化物和叠氮化物适合溶液核磁共振表征。由于氰化物和叠氮化物是结合氧的对比模型，因此表征它们分子和/或电子结构的差异是有意义的。我们报告了脑膜炎奈瑟菌血红素加氧酶的叠氮化物和氰化物底物复合物的详细 2D NMR 比较，揭示了两种复合物之间化学位移的显着且广泛的差异。为了区分两种配合物之间的分子和电子结构变化，确定了叠氮化物配合物的顺磁磁化率张量的各向异性和取向，以便与氰化物配合物进行比较。预测和观察到的偶极位移的比较表明，位移差异很大程度上受电子结构差异的影响，并且除了紧邻远端配体之外，没有提供任何分子结构或氢键可检测差异的证据。易于切割的 C 末端与活性位点相互作用，饱和转移使得高自旋水合复合物中的血红素分配变得困难。
Heme oxygenase carries out stereospecific catabolism of protohemin to yield iron, CO and biliverdin. Instability of the physiological oxy complex has necessitated the use of model ligands, of which cyanide and azide are amenable to solution NMR characterization. Since cyanide and azide are contrasting models for bound oxygen, it is of interest to characterize differences in their molecular and/or electronic structures. We report on detailed 2D NMR comparison of the azide and cyanide substrate complexes of heme oxygenase from Neisseria meningitidis, which reveals significant and widespread differences in chemical shifts between the two complexes. To differentiate molecular from electronic structural changes between the two complexes, the anisotropy and orientation of the paramagnetic susceptibility tensor were determined for the azide complex for comparison with those for the cyanide complex. Comparison of the predicted and observed dipolar shifts reveals that shift differences are strongly dominated by differences in electronic structure and do not provide any evidence for detectable differences in molecular structure or hydrogen bonding except in the immediate vicinity of the distal ligand. The readily cleaved C-terminus interacts with the active site and saturation-transfer allows difficult heme assignments in the high-spin aquo complex.
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影响因子：
15
作者：
Li, YM;Syvitski, RT;La Mar, GN
通讯作者：
La Mar, GN
影响因子：
15
作者：
Caignan, GA;Deshmukh, R;Rivera, M
通讯作者：
Rivera, M
影响因子：
15
作者：
Fujii, H;Zhang, XH;Yoshida, T
通讯作者：
Yoshida, T
影响因子：
15
作者：
Ma, Li-Hua;Liu, Yangzhong;La Mar, Gerd N.
通讯作者：
La Mar, Gerd N.
影响因子：
2.9
作者：
Deshmukh, R;Zeng, YH;Wilks, A
通讯作者：
Wilks, A