In situ two-dimensional crystallization of a polytopic membrane protein: the cardiac gap junction channel
- 1 July 1994
- journal article
- Published by International Union of Crystallography (IUCr) in Acta Crystallographica Section D-Biological Crystallography
- Vol. 50 (4) , 632-638
- https://doi.org/10.1107/s0907444993014313
Abstract
In situ crystallization of rat ventricular gap junctions was accomplished by sequential dialysis of membranes against low concentrations of deoxycholate and dodecyl-beta-D-maltoside. Lipids are removed without solubilizing the protein, and the increased protein concentration in the membrane plane facilitates two-dimensional crystallization in the native membrane environment. The two-dimensional crystals have a nominal resolution of 16 A and display plane group symmetry p6 with a = b = 85 A and gamma = 120 degrees. Electron crystallography reveals that the cardiac gap junction membrane channel is formed by a hexameric cluster of protein subunits, and this hexameric design appears to be a recurring quaternary motif for the multigene family of gap junction proteins. Exposure of membranes to low concentrations of detergents may provide an approach for in situ two-dimensional crystallization of other connexins as well as other membrane proteins, especially those that are labile when solubilized as protein-detergent micelles.Keywords
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