Molecular basis for the inhibition of human NMPRTase, a novel target for anticancer agents
作者:Javed A Khan、Xiao Tao、Liang Tong
DOI:10.1038/nsmb1105
日期:2006.7
Nicotinamide phosphoribosyltransferase (NMPRTase) has a crucial role in the salvage pathway of NAD+ biosynthesis, and a potent inhibitor of NMPRTase, FK866, can reduce cellular NAD+ levels and induce apoptosis in tumors. We have determined the crystal structures at up to 2.1-Ã
resolution of human and murine NMPRTase, alone and in complex with the reaction product nicotinamide mononucleotide or the inhibitor FK866. The structures suggest that Asp219 is a determinant of substrate specificity of NMPRTase, which is confirmed by our mutagenesis studies. FK866 is bound in a tunnel at the interface of the NMPRTase dimer, and mutations in this binding site can abolish the inhibition by FK866. Contrary to current knowledge, the structures show that FK866 should compete directly with the nicotinamide substrate. Our structural and biochemical studies provide a starting point for the development of new anticancer agents.
烟酰胺磷酸核糖基转移酶(NMPRTase)在NAD+生物合成的修复途径中起着关键作用,而NMPRTase的强效抑制剂FK866可以降低细胞中的NAD+水平,并诱导肿瘤细胞凋亡。我们确定了人类和鼠类NMPRTase的晶体结构,分辨率高达2.1Å,包括单独的NMPRTase以及与反应产物烟酰胺单核苷酸或抑制剂FK866的复合物。这些结构表明,Asp219是NMPRTase底物特异性的决定因素,这一点在我们的突变研究中得到证实。FK866结合在NMPRTase二聚体界面上的一个通道中,该结合位点的突变可以消除FK866的抑制作用。与现有知识相反,这些结构表明FK866应该直接与烟酰胺底物竞争。我们的结构和生化研究为开发新的抗癌药物提供了起点。