Maliga Zoltan, Mitchison Timothy J
MPI-CBG, Pfotenhauer Strasse 108, 01307 Dresden, Germany.
BMC Chem Biol. 2006 Feb 27;6:2. doi: 10.1186/1472-6769-6-2.
A recent crystal structure of monastrol in a ternary complex with the kinesin Eg5 motor domain highlights a novel, induced-fit drug binding site at atomic resolution. Mutational obliteration of the monastrol binding site results in a monastrol-resistant, but otherwise catalytically active Eg5 motor domain. However, considering the conformational changes at this site, it is unclear what specific interactions stabilize the interaction between monastrol and the Eg5 motor domain.
To study the molecular complementarity of the monastrol-Eg5 interaction, we used a combination of synthetic chemistry and targeted mutations in Eg5 to measure the contribution of specific contacts to inhibition of Eg5 in vitro and in cultured cells. Structure-activity data on chemical derivatives, sequence analysis of Eg5 homologs from different species, and the effect of mutations near the drug binding site were consistent with the crystal structure.
The mechanism of monastrol revealed by our data rationalizes its specificity for Eg5 over other kinesins and highlights a potential mechanism of drug resistance for anti-cancer therapy targeting this site in Eg5.
最近，单星孢菌素与驱动蛋白Eg5运动结构域形成的三元复合物的晶体结构在原子分辨率下突出显示了一个新的、诱导契合的药物结合位点。单星孢菌素结合位点的突变消除导致产生对单星孢菌素耐药但在其他方面具有催化活性的Eg5运动结构域。然而，考虑到该位点的构象变化，尚不清楚是什么特定相互作用稳定了单星孢菌素与Eg5运动结构域之间的相互作用。
为了研究单星孢菌素与Eg5相互作用的分子互补性，我们结合了合成化学和对Eg5进行靶向突变的方法，以测量特定接触对体外和培养细胞中Eg5抑制作用的贡献。化学衍生物的构效关系数据、来自不同物种的Eg5同源物的序列分析以及药物结合位点附近突变的影响与晶体结构一致。
我们的数据揭示的单星孢菌素作用机制解释了其对Eg5相对于其他驱动蛋白的特异性，并突出了针对Eg5中该位点的抗癌治疗的潜在耐药机制。
