Nonequivalence Observed for the 16-Meric Structure of a Small Heat Shock Protein, SpHsp16.0, from Schizosaccharomyces pombe
Nonequivalence Observed for the 16-Meric Structure of a Small Heat Shock Protein, SpHsp16.0, from Schizosaccharomyces pombe
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DOI：
10.1016/j.str.2012.11.015
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发表时间：
2013-02-05
期刊：
影响因子：
5.7
通讯作者：
Miki, Kunio
中科院分区：
文献类型：
--
作者：
Hanazono, Yuya;Takeda, Kazuki;Miki, Kunio
小热休克蛋白（sHsps）在防止变性蛋白在应激条件下的致命聚集中发挥作用。sHsps在静息状态下以单分散的低聚物存在。由于sHsps的疏水n端区域可能是变性蛋白的相互作用位点，因此寡聚物的组装方式对于激活和失活机制至关重要。本文报道了用x射线晶体学和小角x射线散射技术测定裂糖菌SpHsp16.0的低聚物结构。结果表明，SpHsp16.0的8个二聚体形成一个422对称的细长球体。这些单体在与相邻单体的相互作用以及N端和c端构象中表现出非等效性。n端苯丙氨酸残基的变异表明寡聚物的形成能力与伴侣活性高度相关。本文讨论了结构和生物物理结果与SpHsp16.0激活机制的可能相关性。
Small heat shock proteins (sHsps) play a role in preventing the fatal aggregation of denatured proteins in the presence of stresses. The sHsps exist as monodisperse oligomers in their resting state. Because the hydrophobic N-terminal regions of sHsps are possible interaction sites for denatured proteins, the manner of assembly of the oligomer is critical for the activation and inactivation mechanisms. Here, we report the oligomer architecture of SpHsp16.0 from Schizosaccharomyces pombe determined with Xray crystallography and small angle X-ray scattering. Both results indicate that eight dimers of SpHsp16.0 form an elongated sphere with 422 symmetry. The monomers show nonequivalence in the interaction with neighboring monomers and conformations of the N- and C-terminal regions. Variants for the N-terminal phenylalanine residues indicate that the oligomer formation ability is highly correlated with chaperone activity. Structural and biophysical results are discussed in terms of their possible relevance to the activation mechanism of SpHsp16.0.