Lao Xingzhen, Bao Jingxiao, Yu Tingting, Li Qingqing, Zheng Heng
School of Life Science and Technology, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing, 210009, People's Republic of China.
J Mol Model. 2016 Nov;22(11):281. doi: 10.1007/s00894-016-3147-1. Epub 2016 Oct 29.
Decorsin is an antagonist of platelet glycoprotein integrin αIIbβ3 on platelets; the protein is 39 amino acids long with three disulfide bridges in its tertiary structure. To demonstrate decorsin's mechanism of action, we applied the computational virtual technique and platelet aggregation inhibition assay, which showed that the flanking amino-acid residues of the Arg-Gly-Asp (RGD) motif play an important role in platelet aggregation. The computational simulations revealed that the RGD motif mainly contributes to the stability of the complex when decorsion interacts with integrin αIIbβ3. However, the C-terminal residues, such as 34A→W and 35D→R, was also found to possibly play a key role in their binding structures. Moreover, we produced a decorsin analog (A34W plus D35R decorsin), in which the 34A (alanine) and 35D (aspartic acid) residues were respectively substituted by W (tryptophan) and R (arginine). This isoform was then recombinantly expressed in Escherichia coli. Intriguingly, this mutant type showed higher anti-platelet aggregation activity than the wildtype. Our study may further contribute to finding decorsin mutants with higher anti-platelet aggregation activity.
去皮质素是血小板上血小板糖蛋白整合素αIIbβ3的拮抗剂；该蛋白由39个氨基酸组成，其三级结构中有三个二硫键。为了证明去皮质素的作用机制，我们应用了计算虚拟技术和血小板聚集抑制试验，结果表明精氨酸-甘氨酸-天冬氨酸（RGD）基序两侧的氨基酸残基在血小板聚集中起重要作用。计算模拟表明，当去皮质素与整合素αIIbβ3相互作用时，RGD基序主要有助于复合物的稳定性。然而，还发现C末端残基，如34A→W和35D→R，可能在它们的结合结构中起关键作用。此外，我们制备了一种去皮质素类似物（A34W加D35R去皮质素），其中34A（丙氨酸）和35D（天冬氨酸）残基分别被W（色氨酸）和R（精氨酸）取代。然后该异构体在大肠杆菌中重组表达。有趣的是，这种突变型显示出比野生型更高的抗血小板聚集活性。我们的研究可能会进一步有助于找到具有更高抗血小板聚集活性的去皮质素突变体。
