人水通道蛋白2的4.5埃结构

The 4.5 A structure of human AQP2.

作者信息

Schenk Andreas D, Werten Paul J L, Scheuring Simon, de Groot Bert L, Müller Shirley A, Stahlberg Henning, Philippsen Ansgar, Engel Andreas

机构信息

M. E. Müller Institute for Microscopy, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland.

出版信息

J Mol Biol. 2005 Jul 8;350(2):278-89. doi: 10.1016/j.jmb.2005.04.030.

DOI:10.1016/j.jmb.2005.04.030

PMID:15922355

Abstract

Located in the principal cells of the collecting duct, aquaporin-2 (AQP2) is responsible for the regulated water reabsorption in the kidney and is indispensable for the maintenance of body water balance. Disregulation or malfunctioning of AQP2 can lead to severe diseases such as nephrogenic diabetes insipidus, congestive heart failure, liver cirrhosis and pre-eclampsia. Here we present the crystallization of recombinantly expressed human AQP2 into two-dimensional protein-lipid arrays and their structural characterization by atomic force microscopy and electron crystallography. These crystals are double-layered sheets that have a diameter of up to 30 microm, diffract to 3 A(-1) and are stacked by contacts between their cytosolic surfaces. The structure determined to 4.5 A resolution in the plane of the membrane reveals the typical aquaporin fold but also a particular structure between the stacked layers that is likely to be related to the cytosolic N and C termini.

摘要

水通道蛋白-2（AQP2）位于集合管的主细胞中，负责肾脏中受调节的水重吸收，对维持身体水平衡至关重要。AQP2的调节异常或功能失调会导致严重疾病，如肾性尿崩症、充血性心力衰竭、肝硬化和先兆子痫。在此，我们展示了重组表达的人AQP2结晶形成二维蛋白质-脂质阵列，并通过原子力显微镜和电子晶体学对其进行结构表征。这些晶体是直径达30微米的双层薄片，衍射分辨率达3 Å⁻¹，通过其胞质表面之间的接触堆叠在一起。在膜平面上确定的分辨率为4.5 Å的结构揭示了典型的水通道蛋白折叠，但也揭示了堆叠层之间的一种特殊结构，这种结构可能与胞质N端和C端有关。