Crystallization and preliminary X-ray analysis of the primary receptor (PotD) of the polyamine transport system in Escherichia coli

• Published in: Acta crystallographica. Section D, Biological crystallography. Vol. 52; no. 2; pp. 416 - 418
• Main Authors: Sugiyama, S., Matsushima, M., Saisho, T., Kashiwagi, K., Igarashi, K., Morikawa, K.
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.03.1996
• ISSN: 1399-0047; 0907-4449; 1399-0047
• DOI: 10.1107/S0907444995011498

The primary receptor (potD, Mr = 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 Å resolution, belong to the space group P21, with unit‐cell dimensions a = 145.3, b = 69.1, c = 72.5 Å and β = 107.6°. 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 Å resolution and belong to the space group I41, with unit‐cell dimensions a = b = 130.3 and c = 38.7 Å. They contain one molecule per asymmetric unit.