THE CRYSTAL STRUCTURE OF GLUTATHIONE
THE CRYSTAL STRUCTURE OF GLUTATHIONE
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DOI：
10.1107/s0365110x58001699
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发表时间：
1958-01-01
期刊：
影响因子：
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通讯作者：
WRIGHT, WB
中科院分区：
文献类型：
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作者：
WRIGHT, WB
三肽谷胱甘肽（γ-~.-谷氨酰-~-半胱氨酰-甘氨酸（CxOH ~; NaO~ S）属正交晶系，空间群为P2~ 2~ 2~，晶胞参数a= 28-054-0-02，B-8.802+ 0”002，c= 5”630_0。002 A.根据三维Patterson函数的Harker截面确定了硫原子在晶胞中的位置。最后根据C轴傅立叶投影图确定结构，该投影图基于由Cochran &道格拉斯方法导出的具有符号的项，结合基于仅由硫原子给出的相位角的项的三维电子密度分布使用。通过二维和三维傅立叶合成对结构进行了修正。该分子不含不寻常的键长或键角，并采用卷曲构型，甘氨酸羧基和氨基羧基的平面均平行于c轴，并且平面肽键彼此倾斜94-4。硫原子围绕平行于c的交替螺旋二联体轴形成Z字形链，SS距离为4.41 A。该结构通过氢键的三维网络保持在一起，但分子中没有内部氢键。引言天然存在的三肽谷胱甘肽γ L-谷氨酰基-L-半胱氨酰-甘氨酸，CH~ SH I HOOCCHNH~ CH 2CH ~ CONHCHCONHCH~ COOH，进行了，以期提供更多的信息，分子结构的%特别令人感兴趣的是分子中存在的两个肽连接可能具有与蛋白质链中的骨架肽连接相同的彼此空间关系，已经假定了某些结构，例如α-螺旋（Pauling & Corey，1951）。对于溶液中谷胱甘肽分子的各种结构已经被假定（卡尔文，1954），例如那些涉及与硫原子形成内部氢键的结构，这可以解释在尿素和胍盐存在下谷胱甘肽基团的反应性增加，这也是在蛋白质中观察到的现象。在试结构工作中考虑了这种氢键形成的可能性和分子中存在其他内部氢键的可能性。大多数熟知的晶体结构分析方法都是在初步尝试确定结构的过程中尝试的。试验是在c轴投影上进行的，c轴投影被认为包含最少的重叠，并且具有对称中心的额外优势。结果发现，大多数尝试的方法基本上给出了相同的c轴投影傅立叶图案，可以将分子以各种不同的方式放置在其上;但只有
The tripeptide glutathione (y-~.-glutamyl-~-cysteinyl-glycine, Cx0H~; NaO~ S) crystallizes in the orthorhombie system with space group P2~ 2~ 2~ and unit-cell dimensions a= 28-054-0-02, b----8.802+ 0" 002, c= 5" 630___0. 002 A. The positions of the sulphur atoms in the unit cell were deter-mined from the Harker sections of the three-dimensional Patterson ftmction. The structure was finally determined from a c-axis Fourier projection pattern based on terms with signs derived by the method of Cochran & Douglas, used in conjunction with a three-dimen-sional electron-density distribution based on terms with phase angles given by the sulphur atoms only. The structure was refined by two-and three-dimensional Fourier s:~ ntheses. The molecule contains no unusual bond lengths or angles and adopts a curled configuration with the planes of the glycine carboxyl group and the amino-carboxyl group both parallel to the c-axis, and the planar peptide linkages inclined at 94-4 to one another. The sulphur atoms form zigzag chains about alternate screw diad axes parallel to c, the SS distance being 4.41 A. The structure is held together by a three-dimensional network of hydrogen bonds, but there are no internal hydrogen bonds in the molecule.Introduction The investigation of the crystal structure of the naturally occurring tripeptide glutathione yL-glutamyl-L-cysteinyl-glycine, CH~ SH I HOOCCHNH~ CH2CH~ CONHCHCONHCH~ COOH, was undertaken with a view to providing additional information about the molecular configuration of the% it considered to be of especial interest in that the two peptide linkages present in the molecule might bear the same spatial relationship to one another as do neigh-bouring peptide linkages in protein chains, for which certain structures such as the a-helix have been postulated (Pauling & Corey, 1951). Various structures have been postulated for the glutathione molecule in solution (Calvin, 1954), such as those involving internal hydrogen-bond formation to the sulphur atom, which would account for the increased reactivity of the mercaptan group in the presence of urea and guanidinium salts, a phenomenon also observed with proteins. The possibility of this type of hydrogen-bond formation and of the presence of other internal hydrogen bonds in the molecule was considered during the trial structure work. Most of the well known methods of crystal-structure analysis were tried during the preliminary attempts to determine the structure. The trials were made on the c-axis projection, which was considered to contain the least overlap and has the additional advantage of a centre of symmetry. It was found that most of the methods tried gave essentially the same c-axis projec-tion Fourier pattern, on which it was possible to place the molecule in a variety of different ways; but only