Brush border myosin-I structure and ADP-dependent conformational changes revealed by cryoelectron microscopy and image analysis.
Brush border myosin-I structure and ADP-dependent conformational changes revealed by cryoelectron microscopy and image analysis.
复制标题
刷子边界肌球蛋白-I结构和ADP依赖性构象变化通过冷冻电子显微镜和图像分析揭示。
DOI：
10.1083/jcb.139.3.683
复制
发表时间：
1997-11-03
期刊：
影响因子：
--
通讯作者：
Milligan RA
中科院分区：
文献类型：
--
作者：
Jontes JD;Milligan RA
Brush border myosin–I (BBM-I) is a single-headed myosin found in the microvilli of intestinal epithelial cells, where it forms lateral bridges connecting the core bundle of actin filaments to the plasma membrane. Extending previous observations (Jontes, J.D., E.M. Wilson-Kubalek, and R.A. Milligan. 1995. Nature [Lond.]. 378:751–753), we have used cryoelectron microscopy and helical image analysis to generate three-dimensional (3D) maps of actin filaments decorated with BBM-I in both the presence and absence of 1 mM MgADP. In the improved 3D maps, we are able to see the entire light chain–binding domain, containing density for all three calmodulin light chains. This has enabled us to model a high resolution structure of BBM-I using the crystal structures of the chicken skeletal muscle myosin catalytic domain and essential light chain. Thus, we are able to directly measure the full magnitude of the ADP-dependent tail swing. The ∼31° swing corresponds to ∼63 Å at the end of the rigid light chain–binding domain. Comparison of the behavior of BBM-I with skeletal and smooth muscle subfragments-1 suggests that there are substantial differences in the structure and energetics of the biochemical transitions in the actomyosin ATPase cycle.
