组织的核心形成的哺乳动物的丙酮酸脱氢酶复合物E2和E2加上E3-binding蛋白质和他们的能力来绑定E1和E3组件。
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Hiromasa Y,藤泽T,麻生太郎Y,罗氏TE
组织的核心形成的哺乳动物的丙酮酸脱氢酶复合物E2和E2加上E3-binding蛋白质和他们的能力来绑定E1和E3组件。
J生物化学杂志。2004年2月20日,279(8):6921 - 33所示。Epub 2003年11月24日。
- PubMed ID
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14638692 (在PubMed]
- 文摘
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dihydrolipoyl乙酰转移酶的亚基(E2)组件的哺乳动物的丙酮酸脱氢酶复合体可以通过协会成立60米的c端域E2的十二面体的顶点。这个内核结构外,E2有丙酮酸脱氢酶组件(E1)绑定域后跟两个lipoyl域,所有连接的移动链接器区域。哺乳动物的丙酮酸脱氢酶复合体的组装核心结构还包括dihydrolipoyl脱氢酶(E3)结合蛋白(E3BP)结合我E2的c端域的域。E3BP同样有链接器区域连接一个lipoyl E3-binding域和域。E2的成分。E3BP被认为是大约60 E2 + 12 E3BP。我们准备好的同质人类组件。E2和E2。E3BP年代(20 w)的值36年代和31.8年代,分别。均衡沉降和小角x射线散射研究表明,E2。E3BP has lower total mass than E2, and small angle x-ray scattering showed that E3 binds to E2.E3BP outside the central dodecahedron. In the presence of saturating levels of E1, E2 bound approximately 60 E1 and maximally sedimented 64.4 +/- 1.5 S faster than E2, whereas E1-saturated E2.E3BP maximally sedimented 49.5 +/- 1.4 S faster than E2.E3BP. Based on the impact on sedimentation rates by bound E1, we estimate fewer E1 (approximately 12) were bound by E2.E3BP than by E2. The findings of a smaller E2.E3BP mass and a lower capacity to bind E1 support the smaller E3BP substituting for E2 subunits rather than adding to the 60-mer. We describe a substitution model in which 12 I' domains of E3BP replace 12 I domains of E2 by forming 6 dimer edges that are symmetrically located in the dodecahedron structure. Twelve E3 dimers were bound per E248.E3BP12 mass, which is consistent with this model.