STRUCTURE OF BEEF-LIVER CATALASE
STRUCTURE OF BEEF-LIVER CATALASE
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DOI：
10.1016/0022-2836(81)90254-0
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发表时间：
1981-01-01
影响因子：
5.6
通讯作者：
ROSSMANN, MG
中科院分区：
文献类型：
--
作者：
MURTHY, MRN;REID, TJ;ROSSMANN, MG
牛肝过氧化氢酶的三维结构为2.5埃。通过同晶型和分子置换技术的组合进行拆分。使用矢量搜索和差分傅立叶方法找到重原子的位置。四聚体过氧化氢酶分子具有222对称性，其中一个二分体与晶体学2-折叠轴一致。已知的多肽序列已明确地拟合到电子密度图上。血红素很好地埋在疏水袋中，20埃。在分子的表面之下并且可通过疏水通道进入。血红素口袋里的残基属于2个不同的亚基。Ty 357是近端血红素配体，远端侧上的催化重要残基是残基His 74和Asn 47。三级结构由4个结构域组成：延长的非球形氨基末端臂，其稳定四级结构;反平行的8-链β-氨基末端臂，其稳定四级结构。在血红素的远端侧提供残基的桶;围绕包括近端血红素配体的亚基外部的相当随机的包裹结构域;和最终的α-类似于球蛋白的E、F、G和H螺旋的螺旋结构。
The 3 dimensional structure of beef liver catalase was determined to 2.5 .ANG. resolution by a combination of isomorphous and molecular replacement techniques. Heavy-atom positions were found using vector search and difference Fourier methods. The tetrameric catalase molecule has 222 symmetry with one of its dyads coincident with a crystallographic 2-fold axis. The known polypeptide sequence has been unambiguously fitted to the electron density map. The heme is well buried in a hydrophobic pocket, 20 .ANG. below the surface of the molecule and accessible through a hydrophobic channel. Residues that line the heme pocket belong to 2 different subunits. Ty357 is the proximal heme ligand and the catalytically important residues on the distal side are residues His74 and Asn47. The tertiary structure consists of 4 domains: an extended non-globular amino-terminal arm, which stabilizes the quaternary structure; an anti-parallel, 8-stranded .beta.-barrel providing the residues on the distal side of the heme; a rather random wrapping domain around the subunit exterior including the proximal heme ligand; and a final .alpha.-helical structure resembling the E, F, G and H helices of the globins.