对海兔肌红蛋白中组氨酸（E7）进行工程改造会影响血红素反应性的调控。

Engineering His(E7) affects the control of heme reactivity in Aplysia limacina myoglobin.

作者信息

Federici L, Savino C, Musto R, Travaglini-Allocatelli C, Cutruzzolà F, Brunori M

机构信息

Department of Biochemical Sciences "A. Rossi Fanelli" and C.N.R. Center for Molecular Biology, University of Rome "La Sapienza", Piazzale Aldo Moro 5, Rome, 00185, Italy.

出版信息

Biochem Biophys Res Commun. 2000 Mar 5;269(1):58-63. doi: 10.1006/bbrc.2000.2259.

DOI:10.1006/bbrc.2000.2259

PMID:10694477

Abstract

Aplysia limacina myoglobin lacks the distal histidine (His (E7)) and displays a ligand stabilization mechanism based on Arg(E10). The double mutant Val(E7)His-Arg(E10)Thr has been prepared to engineer the role of His(E7), typical of mammalian myoglobins, in a different globin framework. The 2.0 A crystal structure of Val(E7)His-Arg(E10)Thr met-Mb mutant reveals that the His(E7) side chain points out of the distal pocket, providing an explanation for the observed failure to stabilize the Fe(II) bound oxygen in the ferrous myoglobin. Moreover, spectroscopic analysis together with kinetic data on azide binding to met-myoglobin are reported and discussed in terms of the presence of a water molecule at coordination distance from the heme iron.

摘要

海兔肌红蛋白缺乏远端组氨酸（His (E7)），并表现出基于精氨酸（Arg(E10)）的配体稳定机制。已制备双突变体Val(E7)His-Arg(E10)Thr，以在不同的球蛋白框架中设计典型哺乳动物肌红蛋白中His(E7)的作用。Val(E7)His-Arg(E10)Thr met-Mb突变体的2.0 Å晶体结构表明，His(E7)侧链指向远端口袋外部，这为观察到的亚铁肌红蛋白中结合氧的Fe(II)未能稳定提供了解释。此外，还报告了叠氮化物与高铁肌红蛋白结合的光谱分析以及动力学数据，并根据与血红素铁配位距离处存在水分子的情况进行了讨论。