Binding of Iodide to Arthromyces ramosus Peroxidase Investigated with X-ray Crystallographic Analysis, 1H and 127I NMR Spectroscopy, and Steady-state Kinetics*
Binding of Iodide to Arthromyces ramosus Peroxidase Investigated with X-ray Crystallographic Analysis, 1H and 127I NMR Spectroscopy, and Steady-state Kinetics*
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通过 X 射线晶体分析、1H 和 127I NMR 光谱以及稳态动力学研究碘化物与枝节霉菌过氧化物酶的结合*
DOI：
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发表时间：
1997
影响因子：
4.8
通讯作者：
T. Hosoya
中科院分区：
文献类型：
--
作者：
K. Fukuyama;Koichiro Sato;Hiroyuki Itakura;Seizo Takahashi;T. Hosoya
通过x射线晶体分析、1H和127I核磁共振以及动力学研究，确定了碘化物与大节霉菌过氧化物酶的结合位点和特征。在pH为5.5的KI溶液中浸泡的a . ramosus过氧化物酶晶体x射线分析表明，一个碘离子位于通往血红素远端通道的入口，位于距离血红素铁12.8 Å的两个肽段Phe90-Pro91-Ala92和Ser151-Leu152-Ile153之间。碘离子与血红素外周甲基之间的距离均大于10 Å。与辣根过氧化物酶不同的是，加碘对A. ramosus过氧化物酶超精细位移区的化学位移和甲基强度的影响不大。此外，127I核磁共振和稳态动力学表明，碘离子的结合依赖于一个pKa约为5.3的氨基酸残基的质子化，该残基可能是远端组氨酸（His56），距离碘离子7.8 Å。在此基础上讨论了电子从碘离子向血红素铁转移的机理。
The site and characteristics of iodide binding to Arthromyces ramosus peroxidase were examined by x-ray crystallographic analysis, 1H and 127I NMR, and kinetic studies. X-ray analysis of an A. ramosus peroxidase crystal soaked in a KI solution at pH 5.5 showed that a single iodide ion is located at the entrance of the access channel to the distal side of the heme and lies between the two peptide segments, Phe90-Pro91-Ala92 and Ser151-Leu152-Ile153, 12.8 Å from the heme iron. The distances between the iodide ion and heme peripheral methyl groups were all more than 10 Å. The findings agree with the results obtained with 1H NMR in which the chemical shift and intensity of the methyl groups in the hyperfine shift region of A. ramosus peroxidase were hardly affected by the addition of iodide, unlike the case of horseradish peroxidase. Moreover, 127I NMR and steady-state kinetics showed that the binding of iodide depends on protonation of an amino acid residue with a pKa of about 5.3, which presumably is the distal histidine (His56), 7.8 Å away from the iodide ion. The mechanism of electron transfer from the iodide ion to the heme iron is discussed on the basis of these findings.
DOI：
10.1016/s0021-9258(17)43641-6
发表时间：
1984-01
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
R. Magnusson;A. Taurog;M. Dorris
通讯作者：
R. Magnusson;A. Taurog;M. Dorris
辣根过氧化物酶中间体的时间分辨和静态共振拉曼光谱。
影响因子：
2.9
作者：
Oertling,WA;Babcock,GT
通讯作者：
Babcock,GT
辣根过氧化物酶催化的双电子氧化。
DOI：
--
发表时间：
1993
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Harris,RZ;Newmyer,SL;OrtizdeMontellano,PR
通讯作者：
OrtizdeMontellano,PR