• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Molecular Biology >Artificial protein cavities as specific ligand-binding templates: characterization of an engineered heterocyclic cation-binding site that preserves the evolved specificity of the parent protein.
【24h】

Artificial protein cavities as specific ligand-binding templates: characterization of an engineered heterocyclic cation-binding site that preserves the evolved specificity of the parent protein.

机译：人工蛋白腔作为特定的配体结合模板：保留了亲本蛋白进化特异性的工程化杂环阳离子结合位点的表征。

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

Cavity complementation has been observed in many proteins, where an appropriate small molecule binds to a cavity-forming mutant. Here, the binding of compounds to the W191G cavity mutant of cytochrome c peroxidase is characterized by X-ray crystallography and binding thermodynamics. Unlike cavities created by removal of hydrophobic side-chains, the W191G cavity does not bind neutral or hydrophobic compounds, but displays a strong specificity for heterocyclic cations, consistent with the role of the protein to stabilize a tryptophan radical at this site. Ligand dissociation constants for the protonated cationic state ranged from 6 microM for 2-amino-5-methylthiazole to 1 mM for neutral ligands, and binding was associated with a large enthalpy-entropy compensation. X-ray structures show that each of 18 compounds with binding behavior bind specifically within the artificial cavity and not elsewhere in the protein. The compounds make multiple hydrogen bonds to the cavity walls using a subset of the interactions seen between the protein and solvent in the absence of ligand. For all ligands, every atom that is capable of making a hydrogen bond does so with either protein or solvent. The most often seen interaction is to Asp235, and most compounds bind with a specific orientation that is defined by their ability to interact with this residue. Four of the ligands do not have conventional hydrogen bonding atoms, but were nevertheless observed to orient their most polar CH bond towards Asp235. Two of the larger ligands induce disorder in a surface loop between Pro190 and Asn195 that has been identified as a mobile gate to cavity access. Despite the predominance of hydrogen bonding and electrostatic interactions, the small variation in observed binding free energies were not correlated readily with the strength, type or number of hydrogen bonds or with calculated electrostatic energies alone. Thus, as with naturally occurring binding sites, affinities to W191G are likely to be due to a subtle balance of polar, non-polar, and solvation terms. These studies demonstrate how cavity complementation and judicious choice of site can be used to produce a protein template with an unusual ligand-binding specificity.
机译：在许多蛋白质中已经观察到空洞互补，其中适当的小分子与形成空洞的突变体结合。在此，通过X射线晶体学和结合热力学表征化合物与细胞色素C过氧化物酶的W191G腔突变体的结合。与通过除去疏水性侧链产生的空腔不同，W191G空腔不结合中性或疏水性化合物，但对杂环阳离子表现出很强的特异性，与蛋白质在该位点稳定色氨酸自由基的作用相一致。质子化阳离子状态的配体解离常数范围从2-micro-5-aminothiazole的6 microM到中性配体的1 mM，并且结合与大的焓-熵补偿有关。 X射线结构表明，具有结合行为的18种化合物中的每一种都在人造腔内特异性结合，而不在蛋白质的其他位置结合。在不存在配体的情况下，这些化合物利用蛋白质和溶剂之间的一部分相互作用在空腔壁上形成多个氢键。对于所有配体，每个能够形成氢键的原子都会与蛋白质或溶剂发生这种作用。最常见的相互作用是与Asp235结合，大多数化合物以特定方向结合，该方向由其与该残基相互作用的能力定义。四个配体不具有常规的氢键原子，但是仍然观察到它们的最极性CH键朝向Asp235。两种较大的配体在Pro190和Asn195之间的表面环中诱导了混乱，这种紊乱已被确定为通向空腔的移动门。尽管氢键和静电相互作用占优势，但观察到的结合自由能的微小变化并不容易与氢键的强度，类型或数量或仅与计算出的静电能相关。因此，与天然存在的结合位点一样，对W191G的亲和力很可能是由于极性，非极性和溶剂化术语之间的微妙平衡。这些研究表明，腔互补和位点的明智选择可用于生产具有异常配体结合特异性的蛋白质模板。

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