STRUCTURE OF PHOSPHOLAMBAN/CALCIUM ATPASE COMPLEX

研究计划的长远目标是了解 Ca 2 +-ATP酶的调节及其在控制 心脏的收缩力 受磷蛋白（PLB）是一种完整的膜， 心肌蛋白，是主要的调节机制， β-肾上腺素能刺激被转换成 心肌功能 通过与Ca 2+泵的假定相互作用， 心肌肌浆网（SR）的ATP酶，受磷蛋白降低了心肌细胞的ATP酶活性。 Ca ~（2+）-ATP酶对Ca ~（2+）的亲和力。 人们认为生理效应 改变SR的Ca 2+负荷，这与 收缩性 在分子水平上理解这一过程将 允许设计靶向受磷蛋白的治疗策略， 心脏和平滑肌，在运动医学中具有潜在的益处， 某些疾病状态的治疗（即，充血性肥大 心力衰竭、高血压、冠状动脉疾病和哮喘）。 因此，本研究项目的具体目标是表征 PLB与Ca ~（2+）-ATP酶抑制复合物的结构。 这 将PLB和Ca ~（2+）-ATPase共重组成膜 在高密度的环境中结晶所得的囊泡， 膜的平面。 这两者之间的结构相互作用 蛋白质的研究将在预期的分辨率至少为14 埃冷冻水合电子显微镜和三维螺旋 重建 平行地，PLB将被重构成膜 在高密度的环境中，并在膜的平面中结晶。 这种蛋白质的结构将用冷冻水化电子 显微镜和三维重建。 这些结构将允许 我们具体定义PLB结合位点，PLB的功能形式， PLB和与PLB结合相关的构象变化。 通过这个 资讯，我们将更了解公共小巴的角色， 对心肌收缩力的调节。

The long-term objective of the research proposal is to understand the regulation of the Ca2+-ATPase, and its role in the control of contractility in the heart. Phospholamban (PLB) is an integral membrane protein of cardiac muscle, and is the primary regulatory mechanism by which beta-adrenergic stimulation is transduced into a change in myocardial function. Through a presumed interaction with the Ca2+-pumping ATPase of cardiac sarcoplasmic reticulum (SR), phospholamban decreases the affinity of the Ca2+-ATPase for Ca2+. The physiological effect is thought to be altered Ca2+ loading of the SR which is linked to changes in contractility. Understanding this process at the molecular level will allow the design of therapeutic strategies targeting phospholamban in cardiac and smooth muscle, with potential benefits in sports medicine and the treatment of certain disease states (i.e., hypertrophy, congestive heart failure, hypertension, coronary artery disease, and asthma). Therefore, the specific aim of this research project is to characterize the structure of the inhibitory complex between PLB and Ca2+-ATPase. This will be achieved by co-reconstituting PLB and Ca2+-ATPase into a membrane environment at high density and crystallizing the resultant vesicles in the plane of the membrane. The structural interaction between these two proteins will be studied at an anticipated resolution of at least 14 angstroms by frozen hydrated electron microscopy and 3-dimensional helical reconstruction. In parallel, PLB will be reconstituted into a membrane environment at high density and crystallized in the plane of the membrane. The structure of this protein will be studied by frozen hydrated electron microscopy and 3-dimensional reconstruction. These structures will allow us to specifically define the site of PLB binding, the functional form of PLB, and conformational changes associated with PLB binding. Through this information, we will achieve a better understanding of the role of PLB in the regulation of contractility in cardiac muscle.