PROTON NUCLEAR MAGNETIC-RESONANCE CHARACTERIZATION OF HEME DISORDER IN HEMOPROTEINS
PROTON NUCLEAR MAGNETIC-RESONANCE CHARACTERIZATION OF HEME DISORDER IN HEMOPROTEINS
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DOI：
10.1073/pnas.75.12.5755
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发表时间：
1978-01-01
影响因子：
11.1
通讯作者：
LANGRY, KC
中科院分区：
文献类型：
--
作者：
LAMAR, GN;BUDD, DL;LANGRY, KC
描述了一种用于确定血红素蛋白的血红素口袋内的卟啉的取向的质子NMR方法。在低自旋铁模型化合物的超精细位移血红素甲基共振的图案被证明是特征性地反映了一个本地化的低对称性扰动的位置上的π系统。通过氘化的两个相互转换的甲基共振的氘代重组抹香鲸高铁肌红蛋白氰化物观察到的具体分配导致的结论是，由于脱辅基蛋白质接触的血红素上的低对称性扰动不同的两个蛋白质组分由180度旋转的α-γ介轴。因此，在重构肌红蛋白中的血红素在溶液中是“无序的”，并且重构蛋白质的改变的功能性质不能简单地归因于血红素取代基的局部效应。该NMR技术具有确定相关血红素蛋白中血红素相对取向的适用性，并且可以澄清在几种天然血红素蛋白中观察到的血红素共振加倍的起源。
A proton NMR method is described for determining the orientation of a porphyrin within the heme pocket of a hemoprotein. The pattern of the hyperfine-shifted heme methyl resonances in low-spin ferric model compounds is demonstrated to characteristically reflect the position of a localized low-symmetry perturbation on the pi system. The specific assignments via deuteration of the two interconvertible sets of methyl resonances observed for deuteroporphyrin-reconstituted sperm whale metmyoglobin cyanide lead to the conclusion that the low-symmetry perturbations on the heme due to the apo-protein contacts differ for the two protein components by a 180 degrees rotation about the alpha-gamma meso axis. Hence the heme in the reconstituted myoglobin is "disordered" in solution, and the altered functional properties of the reconstituted protein cannot be simply attributed to the local effect of the heme substituent. This NMR technique has applicability for determining the relative heme orientation in related hemoproteins, and may clarify the origin of doubling of heme resonances observed in several native hemoproteins.