一个模型的zymogene因子XII:洞察到蛋白酶激活
Aleksandr Shamanaev1, Yujie Ma2, Michal B Ponczek3
1Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN.
Blood advances
|January 30, 2025
概括
稳定其开放形状的XII因子 (FXII) 突变增强了其通过血卡利克林 (PKa) 的激活. 这导致布拉迪基宁的释放增加,为FXII监管和相关条件提供了洞察力.
科学领域:
- 生物化学 生化学
- 分子生物学分子生物学
- 血液学 血液学 血液学
背景情况:
- 在血中,XII因子 (FXII) 和prekallikrein (PK) 相互激活.
- 血卡利克林 (PKa) 裂解高分子量基因素 (HK) 释放布拉迪基宁,调节血管度和透性.
- FXII存在于封闭形状,限制了PKa激活,但在表面结合时会转变为开放形状.
研究的目的:
- 使用AlphaFold结构建模人类FXII的封闭形状.
- 研究特定氨基酸残留在维持闭合形状和调节FXII激活中的作用.
- 了解影响FXII构造的突变如何与过度的布拉迪基宁形成有关.
主要方法:
- 关闭人类FXII的生成计算模型.
- 在预测的关键残留物上进行了位点定向的突变发生.
- 通过PKa在体外测试的FXII激活动态.
- 研究了突变的FXII对血中的HK裂变的影响.
主要成果:
- 在Arg36,Glu225,Asp253,Trp268或Lys346的突变显著增加了PKa (>10倍) 的FXII激活.
- 这些突变的FXII变种诱导了HK在血中的快速裂变,这是由于与prekallikrein的增强相互激活引起的.
- 这些发现支持一种模型,其中特定的氨基酸相互作用稳定了溶液中封闭的FXII构型.
结论:
- 特定的氨基酸替代破坏了封闭的FXII构造,导致过度激活.
- 涉及这些残留物的形状变化对于表面结合时的FXII激活至关重要.
- 了解这些机制可以了解涉及布拉迪基宁失调的FXII相关疾病.
相关概念视频
Extrinsic and Intrinsic Pathways of Hemostasis
5.0K
Blood clotting or coagulation involves extrinsic and intrinsic pathways, which ultimately merge into the common pathway, forming a fibrin clot.
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which...
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which...
5.0K
Caspases
12.1K
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...
12.1K
Amplifying Signals via Enzymatic Cascade
8.2K
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze...
8.2K
Enzymes
80.5K
Inside living organisms, enzymes act as catalysts for many biochemical reactions involved in cellular metabolism. The role of enzymes is to reduce the activation energies of biochemical reactions by forming complexes with its substrates. The lowering of activation energies favor an increase in the rates of biochemical reactions.
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
80.5K
Role of Matrix Metalloproteases in Degradation of ECM
2.3K
Matrix metalloproteases (MMPs) are enzymes involved in the hydrolysis of proteins and glycoproteins of the extracellular matrix. MMPs are essential for the migration and proliferation of cells through the dense matrix network, throughout embryonic development, and throughout morphogenesis. The first MMP activity discovered was a collagenase in a tadpole's tail undergoing metamorphosis. The active collagen deposition and modifications lead to the morphogenesis of tadpoles into the adult...
2.3K


