基转移反应中的五共价中间体
Sushmita D Lahiri1, Guofeng Zhang, Debra Dunaway-Mariano
1Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118-2394, USA.
概括
研究人员捕获了酶催化过程中高能中间体的原子结构. 这揭示了酶如何稳定过渡状态,解释了它们在转移反应中的显著催化能力.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 酶学 是一种酶学.
背景情况:
- 酶是强大的生物催化剂,通过稳定高能反应状态来实现显著的速度增强.
- 了解酶机制需要可视化这些短暂的,高能量的中间体.
研究的目的:
- 在酶性转移过程中确定高能反应中间体的原子分辨率结构.
- 通过观察酶活性部位的稳定过渡状态来阐明催化功能的机制.
主要方法:
- 化β-酸葡萄糖酶与Mg (II) 辅因子和基质 (葡萄糖1-酸盐或葡萄糖6-酸盐) 的结晶.
- 对酶-Mg(II) -葡萄糖1,6-(bis) 酸盐复合物的X射线衍射分析以原子分辨率 (1.2和1.4安格斯特罗姆).
主要成果:
- 揭示了稳定五对价酸中间体的原子结构.
- 这种中间体是在从葡萄糖1,6-(bis) 酸转移到活性部位的酸残留物 (Asp8) 时形成的.
结论:
- 该研究提供了酶催化中稳定高能中间体的直接结构证据.
- 这种稳定机制,涉及五对应,是酶在转移中的催化效率的关键.
相关概念视频
Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
Energy Transfer in Chemical Reactions
Chemical reactions require sufficient energy to cause the matter to collide with enough precision and force that old chemical bonds can be broken and new ones formed. In general, kinetic energy is the form of energy powering any type of matter in motion. Imagine a person building a brick wall. The energy it takes to lift and place one brick on top of another is the kinetic energy—the energy matter possesses because of its motion. Once the wall is in place, it stores potential energy. Potential...
Transport Number
The transport number is the fraction of the total current carried by an ion in an electrolyte solution. It is defined as the ratio of the current carried by a specific ion to the total current flowing through the solution. The transport number, t, is central to understanding ionic mobility, which describes how fast an ion moves under the influence of an electric field. This link connects the physical behavior of ions in solution to the chemical processes that occur during electrochemical...
Transition State Theory
Transition-state theory, also known as activated-complex theory, provides a molecular-level explanation of reaction rates in both gas-phase and solution-phase reactions. It extends earlier kinetic models by considering the formation of a short-lived, high-energy configuration during a reaction.The progress of a chemical reaction can be represented using a reaction profile, which plots potential energy against the reaction coordinate. As two reactant molecules approach one another, their...


