• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Molecular Biology >Denatured state thermodynamics: residual structure, chain stiffness and scaling factors.
【24h】

Denatured state thermodynamics: residual structure, chain stiffness and scaling factors.

机译：变性状态热力学：残余结构，链刚度和比例因子。

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

A set of nine variants of yeast iso-1-cytochrome c with zero or one surface histidine have been engineered such that the N-terminal amino group is acetylated in vivo. N-terminal acetylation has been confirmed by mass spectral analysis of intact and proteolytically digested protein. The histidine-heme loop-forming equilibrium, under denaturing conditions (3 M guanidine hydrochloride), has been measured by pH titration providing an observed pK(a), pK(a)(obs), for each variant. N-terminal acetylation prevents the N-terminal amino group-heme binding equilibrium from interfering with measurements of histidine-heme affinity. Significant deviation is observed from the linear dependence of pK(a)(obs) on the log of the number of monomers in the loop formed, expected for a random coil denatured state. The maximum histidine-heme affinity occurs for a loop size of 37 monomers. For loop sizes of 37-83 monomers, histidine-heme pK(a)(obs) values are consistent with a scaling factor of -4.2+/-0.3. This value is much larger than the scaling factor of -1.5 for a freely jointed random coil, which is commonly used to represent the conformational properties of protein denatured states. For loop sizes of nine to 22 monomers, chain stiffness is likely responsible for the decreases in histidine-heme affinity relative to a loop size of 37. The results are discussed in terms of residual structure and sequence composition effects on the conformational properties of the denatured states of proteins. Copyright 2001 Academic Press.
机译：已经设计了一组具有零个或一个表面组氨酸的酵母异-1-细胞色素c的九个变体，以使N端氨基在体内被乙酰化。 N末端乙酰化已通过完整和蛋白水解消化的蛋白质的质谱分析得到证实。在变性条件下（3 M盐酸胍），已通过pH滴定法测量了组氨酸-血红素环形成平衡，从而为每个变异提供了观察到的pK（a），pK（a）（obs）。 N-末端乙酰化可防止N-末端氨基-血红素结合平衡干扰组氨酸-血红素亲和力的测量。从pK（a）（obs）与所形成的环中单体数的对数的线性相关性中观察到显着偏差，这对于无规线圈变性状态是预期的。组氨酸大小的最大血红素亲和力出现在37个单体的环上。对于37-83个单体的环大小，组氨酸-血红素pK（a）（obs）值与-4.2 +/- 0.3的比例因子一致。对于自由连接的随机线圈，该值远大于-1.5的比例因子，该比例因子通常用于表示蛋白质变性状态的构象性质。对于9至22个单体的环大小，相对于37环大小，链刚度可能是组氨酸-血红素亲和力下降的原因。讨论了残基和序列组成对变性构象性质的影响的结果。蛋白质状态。版权所有2001学术出版社。

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