Crystallization and preliminary X-ray analysis of the primary receptor (PotD) of the polyamine transport system in Escherichia coli
- 1 March 1996
- journal article
- Published by International Union of Crystallography (IUCr) in Acta Crystallographica Section D-Biological Crystallography
- Vol. 52 (2) , 416-418
- https://doi.org/10.1107/s0907444995011498
Abstract
The primary receptor (potD, M(r) = 39 000) of the polyamine transport system in Escherichia coli has been crystallized by the vapor-diffusion method. Two crystal forms were obtained in the presence of spermidine, and were examined by X-ray analysis. Form I crystals, which diffract to 2.5 A resolution, belong to the space group P2(1), with unit-cell dimensions a = 145.3, b = 69.1, c = 72.5 A and beta = 107.6 degrees. Four molecules are contained in an asymmetric unit. These form two dimers that are related to each other by a local translation of about half of the unit cell along the a axis. The two protein molecules in each dimer are similarly related by a local dyad. Form II crystals diffract to 1.8 A resolution and belong to the space group I4(1), with unit-cell dimensions a = b = 130.3 and c = 38.7 A. They contain one molecule per asymmetric unit.Keywords
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