背景:组织因子(TF),跨膜糖蛋白,在组织因子-因子VIIa(TF-FVIIa)复合物的形成中起着深远的作用,该复合物启动因子Xa(FXa)的产生,然后进行凝血酶激活和凝块形成。以前的报道表明,细胞表面的TF-FVIIa凝血活性可能受到各种过程的影响。包括胆固醇含量的变化和TF的翻译后修饰。进行了许多研究,但没有得出关于胆固醇对TF表达的影响的结论性结果。
目的:本研究旨在了解胆固醇如何影响组织因子-因子VIIa-因子Xa三元复合物(TF-FVIIa-FXa)的结构调节。此外,我们旨在说明棕榈酰化对TF的Cys245残基的影响,并了解其对TF-FVIIa-FXa的结构影响。
方法:我们在不同的脂质环境中建立了以下4种系统:POPC中的TF-FVIIa-FXa:POPS(CS),TF-FVIIa-FXa在POPC:POPS:CHOL(CSL),POPC:POPS:CHOL(CSLP)中的棕榈酰化TF-FVIIa-FXa,和POPC中的棕榈酰化TF-FVIIa-FXa:CHOL(CLP),分别,并对它们进行分子动力学模拟。
结果:在TF-FVIIa-FXa的各种重要结构域与显著的新型相互作用之间进行了氢键和接触概率分析:Asn93FVIIa:L-Lys48TF,Arg178FVIIa:H-Asp95FXa:B,Lys20FVIIa:H-Glu193FXa:A,Arg178FVIIa:H-Asp97FXa:B,已经报道了Arg153FVIIa:H-Gln135FXa:B。蛋白质稳定性研究暗示CS和CLP系统在热力学上不如CSL和CSLP系统稳定。
结论:分子动力学模拟数据的分析表明,胆固醇和棕榈酰化的存在可能有助于结构刚性,稳定性,通过增强蛋白质-蛋白质和蛋白质-脂质相互作用,TF-FVIIa-FXa关键结构域的紧密度。
Tissue factor (TF), a transmembrane glycoprotein, plays a profound role in the formation of the tissue factor-factor VIIa (TF-FVIIa) complex that initiates factor Xa (FXa) generation followed by thrombin activation and clot formation. Previous reports suggest that TF-FVIIa coagulant activity at the cell surface may be affected by various processes, including changes in cholesterol content and posttranslational modifications of TF. Numerous studies were conducted but yielded inconclusive results about the effect of cholesterol on TF expression.
The present
study aimed to understand how cholesterol affects structural modulations on the tissue factor-factor VIIa-factor Xa ternary complex (TF-FVIIa-FXa). Additionally, we aimed to illustrate the effect of palmitoylation on the Cys245 residue of TF and understand its structural implications on the TF-FVIIa-FXa.
We set up the following 4 systems in different lipid environments: TF-FVIIa-FXa in POPC:POPS (CS), TF-FVIIa-FXa in POPC:POPS:CHOL (CSL), Palmitoylated TF-FVIIa-FXa in POPC:POPS:CHOL (CSLP), and Palmitoylated TF-FVIIa-FXa in POPC:CHOL (CLP), respectively, and subjected them to molecular dynamics simulation.
Hydrogen-bond and contact probability analysis were performed between various important domains of TF-FVIIa-FXa and notable novel interactions: Asn93FVIIa:L-Lys48TF, Arg178FVIIa:H-Asp95FXa:B, Lys20FVIIa:H-Glu193FXa:A, Arg178FVIIa:H-Asp97FXa:B, and Arg153FVIIa:H-Gln135FXa:B have been reported. The protein stability
study implies that the CS and CLP systems are thermodynamically less stable than CSL and CSLP systems.
Analysis of molecular dynamic simulation data suggests that the presence of cholesterol and palmitoylation may contribute to structural rigidity, stability, and compactness of key domains of TF-FVIIa-FXa by augmenting protein-protein and protein-lipid interactions.