...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >The roles of conserved amino acids on substrate binding and conformational integrity of ClpB N-terminal domain
【24h】

The roles of conserved amino acids on substrate binding and conformational integrity of ClpB N-terminal domain

机译：保守氨基酸对ClpB N-末端结构域的底物结合和构象完整性的作用

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Escherichia coli heat shock protein ClpB disaggregates denatured protein in cooperation with the DnaK chaperone system. Several studies showed that the N-terminal domain is essential for the chaperone activity, but its role is still largely unknown. The N-terminal domain contains two structurally similar subdomains, and conserved amino acids Thr7 and Ser84 share the same position in two apparent sequence repeats. T7A and S84A substitutions affected chaperone activity of ClpB without significantly changing the native conformation [Liu, Z. et al. ( 2002) J. Mol. Biol. 321, 111-120]. In this study, we aimed to better understand the roles of several conserved amino acid residues, including Thr7 and Ser84, in the N-terminal domain. We investigated the effects of mutagenesis on substrate binding and conformational states of ClpB N-terminal domain fragment (ClpBN). Fluorescence polarization analysis showed that the T7A and S84A substitutions enhanced the interaction between ClpBN and protein aggregates. Interestingly, further analyses suggested that the mechanisms by which they do so are quite different. For T7A substitution, the increased substrate affinity could be due to a conformational change in the hydrophobic core as revealed by NMR spectroscopy. In contrast, for S84A, increased substrate binding would be explained by a unique conformational state of this mutant as revealed by pressure perturbation analysis. The thermal transition temperature of the S84A mutant, monitored by DSC, was 6.1 degrees C lower than that of wild-type. Our results revealed that conserved amino acids Thr7 and Ser84 both participated in maintaining the conformational integrity of the ClpB N-terminal domain.
机译：大肠杆菌热休克蛋白ClpB与DnaK分子伴侣系统协同降解变性蛋白。几项研究表明，N末端结构域对于分子伴侣的活性至关重要，但其作用仍然未知。 N末端结构域包含两个结构相似的亚结构域，并且保守氨基酸Thr7和Ser84在两个明显的序列重复中共享相同的位置。 T7A和S84A取代会影响ClpB的分子伴侣活性，而不会显着改变天然构象[Liu，Z.等。 （2002）J.Mol。生物学321，111-120]。在这项研究中，我们旨在更好地了解N末端域中几个保守的氨基酸残基（包括Thr7和Ser84）的作用。我们调查了诱变对底物结合和ClpB N末端域片段（ClpBN）的构象状态的影响。荧光偏振分析表明，T7A和S84A取代增强了ClpBN与蛋白质聚集体之间的相互作用。有趣的是，进一步的分析表明，这样做的机制是完全不同的。对于T7A取代，增加的底物亲和力可能是由于NMR光谱揭示了疏水核中的构象变化。相反，对于S84A，增加的底物结合将通过该突变体的独特构象状态来解释，如通过压力扰动分析所揭示的。通过DSC监测的S84A突变体的热转变温度比野生型低6.1℃。我们的结果表明，保守的氨基酸Thr7和Ser84都参与维持ClpB N端结构域的构象完整性。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号