Crystallization and preliminary X-ray crystallographic analysis of native and selenomethionyl recombinant tabtoxin-resistance protein complexed with acetyl-coenzyme A

Tabtoxin-resistance protein (TTR), an acetyltransferase from Pseudomonas sy ringae pv. tabaci, was overexpressed in Eschericha coli M15 and the TTR fus ion protein complexed with acetyl-coenzyme A (AcCoA) was purified and cryst allized. Diffraction data were collected to 3.0 Angstrom resolution in-hous e and the crystal was found to belong to space group P2(1), with unit-cell parameters a = 47.6, b = 66.6, c = 53.5 Angstrom, beta = 104.3 degrees. Fur thermore, a selenomethionine (SeMet) TTR fusion protein derivative was over expressed in the same expression system and its complex with AcCoA was puri fied in a reductive environment. The SeMet TTR derivative crystallized in t wo forms: the first was identical to that observed for native crystals and the second belonged to space group C2, with unit-cell parameters a = 101.7, b = 45.6, c = 84.2 Angstrom, beta = 105.8 degrees. Data from the P2(1) cry stal form were collected in-house to 2.3 Angstrom resolution. Subsequently, three different wavelength data sets of the C2 crystal form to 1.55 Angstr om resolution were collected at the Advanced Photon Source at Argonne Natio nal Laboratory.