Crystallization and preliminary X-ray analysis of a C-terminal TonB fragment fromEscherichia coli

Abstract

The TonB protein located in the cell wall of Gram-negative bacteria mediates the proton motive force from the cytoplasmic membrane to speci®c outer membrane transporters. A C-terminal fragment of TonB from Escherichia coli consisting of amino-acid residues 147±239 (TonB-92) has been puri®ed and crystallized. Crystals grew in space group P2 1 to dimensions of about 1.0 Â 0.12 Â 0.12 mm. A native data set has been obtained to 1.09 A Ê resolution.

Crystal Structure of a 92-Residue C-terminal Fragment of TonB from Escherichia coli Reveals Significant Conformational Changes Compared to Structures of Smaller TonB Fragments

“…Crystallization and Data Collection-Crystallization and data collection of native TonB-92 at 1.08-Å resolution has been described elsewhere (28). Crystals of selenomethionine-substituted TonB-92 were grown in 100 mM imidazole, pH 8.0, 1.1 M sodium citrate, and 100 mM sodium chloride using the hanging-drop method.…”