Protection of GroEL by its methionine residues against oxidation by hydrogen peroxide.
Protection of GroEL by its methionine residues against oxidation by hydrogen peroxide.
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通过其蛋氨酸残基保护 GroEL 免受过氧化氢的氧化。
DOI：
10.1016/j.bbrc.2006.06.136
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发表时间：
2006
影响因子：
3.1
通讯作者：
J. A. Mendoza
中科院分区：
文献类型：
--
作者：
G. Melkani;Justin Kestetter;R. Sielaff;G. Zardeneta;J. A. Mendoza
GroEL在过氧化氢（H2 O2）浓度为15 - 20 mM时发生重要的功能和结构转变。当GroEL与15 mM H_2O_2孵育3 h时，其四级结构、伴侣蛋白和ATP酶活性仍保持不变。在这些条件下，GroEL的半胱氨酸和酪氨酸残基保持完整。然而，在这些条件下，分子伴侣的所有甲硫氨酸残基被氧化为相应的甲硫氨酸亚砜。通过溴化氰不能在修饰的甲硫氨酸残基的羧基侧裂解来验证甲硫氨酸残基的氧化。尚未确定GroEL中大量（23个）蛋氨酸残基的作用。据报道，蛋氨酸残基在蛋白质中对生物系统中产生的各种氧化剂（包括H2 O2）具有抗氧化活性。GroEL的羧基末端结构域富含甲硫氨酸残基，我们假设这些残基通过清除H2 O2参与保护GroEL的功能结构。当GroEL进一步孵育相同的时间，但随着H2 O2浓度的增加（> 15 mM），观察到GroEL的半胱氨酸残基的氧化和由于形成二酪氨酸而导致的酪氨酸荧光的显著降低。此外，在这些较高浓度的H2 O2，GroEL水解ATP和协助尿素未折叠的罗丹酸的重折叠的能力被观察到。
GroEL undergoes an important functional and structural transition when oxidized with hydrogen peroxide (H2O2) concentrations between 15 and 20mM. When GroEL was incubated for 3h with 15mM H2O2, it retained its quaternary structure, chaperone and ATPase activities. Under these conditions, GroEL’s cysteine and tyrosine residues remained intact. However, all the methionine residues of the molecular chaperone were oxidized to the corresponding methionine-sulfoxides under these conditions. The oxidation of the methionine residues was verified by the inability of cyanogen bromide to cleave at the carboxyl side of the modified methionine residues. The role for the proportionately large number (23) of methionine residues in GroEL has not been identified. Methionine residues have been reported to have an antioxidant activity in proteins against a variety of oxidants produced in biological systems including H2O2. The carboxyl-terminal domain of GroEL is rich in methionine residues and we hypothesized that these residues are involved in the protection of GroEL’s functional structure by scavenging H2O2. When GroEL was further incubated for the same time, but with increasing concentrations of H2O2(>15mM), the oxidation of GroEL’s cysteine residues and a significant decrease of the tyrosine fluorescence due to the formation of dityrosines were observed. Also, at these higher concentrations of H2O2, the inability of GroEL to hydrolyze ATP and to assist the refolding of urea-unfolded rhodanese was observed.
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DOI：
10.1006/bbrc.2001.6171
发表时间：
2002-01-11
影响因子：
3.1
作者：
Moskovitz, J;Singh, VK;Stadtman, ER
通讯作者：
Stadtman, ER
伴侣蛋白 60 和线粒体硫氰酸酶之间稳定、可重新激活的复合物的表征。
DOI：
--
发表时间：
1992
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Mendoza,JA;Butler,MC;Horowitz,PM
通讯作者：
Horowitz,PM
应激蛋白 GroEL 对 ATP 的较低水解是导致低温下伴侣蛋白活性降低的主要因素。
DOI：
10.1006/cryo.2000.2287
发表时间：
2000
期刊：
Cryobiology.
影响因子：
--
作者：
Mendoza,JA;Dulin,P;Warren,T
通讯作者：
Warren,T
来自大肠杆菌的伴侣蛋白 cpn60 可保护线粒体酶硫氰酸酶免受热失活，并支持高温下的折叠。
DOI：
--
发表时间：
1992
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Mendoza,JA;Lorimer,GH;Horowitz,PM
通讯作者：
Horowitz,PM
通过低pH柱层析纯化牛肝硫氰酸酶。
影响因子：
1.6
作者：
Kurzban,GP;Horowitz,PM
通讯作者：
Horowitz,PM