长期以来,已知αIIbβ-螺旋桨结构域的突变会破坏αIIbβ3复合物的异源二聚化和细胞内运输,从而导致表面表达和/或功能降低。导致Glanzmann血栓形成.我们以前对三个β-螺旋桨突变的研究,即G128S,S287L,和G357S,显示与患者临床表型相关的蛋白质转运缺陷。脉冲追踪实验揭示了三种突变中αIIbβ3复合物成熟的差异。因此,当前的研究旨在将它们各自引起的构象变化联系起来。进化保护分析,稳定性分析,并对三种突变结构进行了分子动力学模拟。稳定性分析表明,而G128S和G357S突变使β-螺旋桨结构不稳定,S287L保持稳定。野生型和突变型β-螺旋桨结构,当进行分子动力学模拟时,证实G128S和G357S与野生型和S287L相比,根据研究的几个参数,像RMSD,RMSF,Rg,FEL,PCA,二级结构,和氢键。在我们之前的研究中,我们证明了突变型S287LαIIbβ3复合物比野生型αIIbβ3复合物更稳定,正如脉冲追踪实验所证明的那样。这些发现证实了由于这些β-螺旋桨突变而导致的突变αIIbβ3复合物的可变细胞内命运。
Mutations in the αIIb β-propeller domain have long been known to disrupt heterodimerization and intracellular trafficking of
αIIbβ3 complexes leading to diminished surface expression and/or function, resulting in Glanzmann thrombasthenia. Our previous study on three β-propeller mutations, namely G128S, S287L, and G357S, showed variable defects in protein transport correlated with the patient\'s clinical phenotypes. Pulse-chase experiments revealed differences in
αIIbβ3 complex maturation among the three mutations. Hence, the current study aims to correlate conformational changes caused by each one of them. Evolutionary conservation analysis, stability analysis, and molecular dynamics simulations of the three mutant structures were carried out. Stability analysis revealed that, while G128S and G357S mutations destabilized the β-propeller structure, S287L retained the stability. Wild-type and mutant β-propeller structures, when subjected to molecular dynamics simulations, confirmed that G128S and G357S were both destabilizing in nature when compared with the wild-type and S287L based on several parameters studied, like RMSD, RMSF, Rg, FEL, PCA, secondary structure, and hydrogen bonds. In our previous study, we demonstrated that mutant S287L
αIIbβ3 complexes were more stable than the wild-type
αIIbβ3 complexes, as evidenced in pulse-chase experiments. These findings corroborate variable intracellular fates of mutant
αIIbβ3 complexes as a result of these β-propeller mutations.