Interface mutation in heptameric co-chaperonin protein 10 destabilizes subunits but not interfaces.
Interface mutation in heptameric co-chaperonin protein 10 destabilizes subunits but not interfaces.
复制标题
七聚体辅助伴侣蛋白 10 中的界面突变会破坏亚基的稳定性，但不会破坏界面的稳定性。
DOI：
10.1016/j.abb.2005.05.019
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Wittung-Stafshede,Pernilla
中科院分区：
文献类型：
--
作者：
Brown,Christopher;Liao,Jue;Wittung-Stafshede,Pernilla
我们在此报道了一种人类线粒体共伴侣蛋白10 （cpn10）变异，其中保守的界面残基亮氨酸-96被甘氨酸取代（Leu96Gly cpn10）。根据超离心分析，突变不会干扰组装成七聚体的能力，电子显微镜显示，Leu96Gly cpn10与野生型cpn10一样呈环状。尽管消除了疏水残基，但在Leu96Gly cpn10和野生型cpn10中，亚基-亚基亲和性基本相同。从交联和凝胶过滤实验中可以明显看出，这可以用Leu96Gly cpn10的补偿重排来解释。作为单体稳定性较低的直接结果，与野生型cpn10相比，Leu96Gly cpn10对化学和热扰动的稳定性显着降低。我们认为亮氨酸-96是为了保证cpn10单体的稳定性而保留的界面残基。我们的研究表明，cpn10界面可以适应结构改变，而不会失去亚基-亚基亲和性或七聚体特异性。
We here report on a human mitochondrial co-chaperonin protein 10 (cpn10) variant in which the conserved interface residue leucine-96 is replaced with glycine (Leu96Gly cpn10). According to analytical ultracentrifugation, the mutation does not perturb the ability to assemble into a heptamer and electron microscopy reveals that Leu96Gly cpn10 is ring-shaped like wild-type cpn10. Despite elimination of a hydrophobic residue, the subunit–subunit affinity is essentially identical in Leu96Gly cpn10 and in wild-type cpn10. This is explained by a compensating rearrangement in Leu96Gly cpn10, evident from cross-linking and gel-filtration experiments. As a direct result of lower monomer stability, Leu96Gly cpn10 is dramatically less stable towards chemical and thermal perturbations as compared to wild-type cpn10. We conclude that leucine-96 is an interface residue preserved to guarantee stable cpn10 monomers. Our study demonstrates that the cpn10 interfaces can adapt to structural alterations without loss of either subunit–subunit affinity or heptamer specificity.