由caspase-8/p35复合物的晶体结构揭示的共价抑制
1Department of Biochemistry, Weill Medical College of Cornell University, New York, New York, 10021 USA
Nature
|March 22, 2001
概括
细菌病毒p35蛋白质通过抑制caspases来防止细胞亡. 结构和生物化学研究揭示了一个新的机制,其中p35形成了共价键,阻断了酶活性,并提供了广泛的蛋白酶抑制.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 结构生物学 结构生物学
背景情况:
- 亡是一个调节的过程,对多细胞生物的发育和恒温至关重要.
- 百科病毒p35蛋白质是已知的抑制剂通过广泛的caspase抑制的亡.
研究的目的:
- 为了阐明p35介导的caspase抑制的分子机制.
- 确定p35与人体caspase-8.8复合体中的晶体结构.
主要方法:
- 进行X射线晶体学,以获得p35-caspase-8复合物的3.0 Å结构.
- 生物化学测定和突变发生研究,以验证结构发现.
主要成果:
- 结构揭示了p35和caspase-8活性位点之间的一种共价硫链接.
- 裂变诱导p35的形状变化,重新定位其N端以阻止活性部位.
- 在p35的N端突变取消了抑制活性,证实了它的作用.
结论:
- p35采用一种新的酶抑制机制,涉及共价链接和构造变化.
- p35的N端对稳定抑制和防止中间水解至关重要.
- 在活性部位以外的保存接触有助于p35的广泛抑制活性.
相关概念视频
Enzyme Inhibition
Inhibitors are molecules that reduce enzyme activity by binding to the enzyme. In a normally functioning cell, enzymes are regulated by a variety of inhibitors. Drugs and other toxins can also inhibit enzymes. Some inhibitors bind to the enzyme’s active site, while others inhibit enzymatic activity by binding to other sites on the protein structure.
Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
Inhibition of Cdk Activity
The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
Caspases
Caspase, a family of cysteine proteases, serve as effectors in apoptosis. The ced3 gene in C.elegans was first identified to be involved in apoptosis. This gene encodes the ced-3 caspase that is similar to the interleukin-1-beta converting enzyme or ICE in mammals. In addition to apoptosis, caspases also function in the inflammatory response. Inflammatory caspases are essential in activating pro-inflammatory cytokines that recruit immune cells and block the replication of pathogens inside cells.
Covalently Linked Protein Regulators
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.
These groups modify specific amino acids in a protein.
Inhibition of CDK Activity
The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...


