A model for the misfolded bis-His intermediate of cytochrome c: the 1-56 N-fragment.
A model for the misfolded bis-His intermediate of cytochrome c: the 1-56 N-fragment.
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细胞色素 c 的错误折叠双组氨酸中间体的模型：1-56 N 片段。
DOI：
10.1016/j.jinorgbio.2004.02.026
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发表时间：
2004
影响因子：
3.9
通讯作者：
G. Smulevich
中科院分区：
文献类型：
--
作者：
E. Santoni;Silvia Scatragli;F. Sinibaldi;L. Fiorucci;R. Santucci;G. Smulevich
本文用紫外-可见吸收光谱和共振拉曼（RR）散射光谱研究了马心细胞色素c（cyt c）含血红素（1-56个残基）N片段在不同pH值和低离子强度下的铁态和亚铁态。在相同的实验条件下，这可能会提供一个更深入的了解细胞色素c的展开折叠过程中的天然细胞色素c的结果进行了比较。细胞色素c的折叠导致血红素铁与组氨酸（His 18）和甲硫氨酸（Met 80）配位的状态。在中性pH下，N-片段（缺乏Met 80）显示出与双-His低自旋血红素的存在一致的吸收和RR光谱，就像亲本蛋白质的几种非天然形式。特别是，在高浓度的变性剂的存在下的光谱是相同的细胞色素C的，这使得N-片段的一个合适的模型来研究血红素口袋微环境的错误折叠（His-His）的中间体形成的折叠过程中的细胞色素C。酸性pH影响cyt c和N片段的连接状态。作为pH值的函数获得的数据允许在N-片段的血红素口袋中的结构特性和那些非天然形式的细胞色素C之间的相关性。结果强调，（57-104个残基）段在天然样条件下，通过阻止溶剂进入血红素口袋赋予蛋白质结构稳定性。
We have characterized the ferric and ferrous forms of the heme-containing (1–56 residues) N-fragment of horse heart cytochrome c (cyt c) at different pH values and low ionic strength by UV–visible absorption and resonance Raman (RR) scattering. The results are compared with native cyt c in the same experimental conditions as this may provide a deeper insight into the cyt c unfolding-folding process. Folding of cyt c leads to a state having the heme iron coordinated to a histidine (His18) and a methionine (Met80) as axial ligands. At neutral pH the N-fragment (which lacks Met80) shows absorption and RR spectra that are consistent with the presence of a bis-His low spin heme, like several non-native forms of the parental protein. In particular, the optical spectra are identical to those of cyt c in the presence of a high concentration of denaturants; this renders the N-fragment a suitable model to study the heme pocket microenvironment of the misfolded (His–His) intermediate formed during folding of cyt c. Acid pH affects the ligation state in both cyt c and the N-fragment. Data obtained as a function of pH allow a correlation between the structural properties in the heme pocket of the N-fragment and those of non-native forms of cyt c. The results underline that the (57–104 residues) segment under native-like conditions imparts structural stability to the protein by impeding solvent access into the heme pocket.
DOI：
10.1073/pnas.94.5.1779
发表时间：
1997-03-04
影响因子：
11.1
作者：
Chan, CK;Hu, Y;Hofrichter, J
通讯作者：
Hofrichter, J
通过血红素结合进行细胞色素 c 肽片段的结构组织。
DOI：
10.1006/jmbi.1998.2341
发表时间：
1999
期刊：
Journal of molecular biology.
影响因子：
--
作者：
Kang,X;Carey,J
通讯作者：
Carey,J
影响因子：
2.9
作者：
Colon, W;Wakem, LP;Roder, H
通讯作者：
Roder, H