Purification, characterization and crystallization of Acanthamoeba profilin expressed in Escherichia coli

Profilin (isoform I) from Acanthamoeba castellani was expressed in Escherichia coli using a bacteriophage T7-based expression vector. The recombinant material is similar to authentic profilin from Acanthamoeba-based on fluorescence monitored urea denaturation, circular dichroism, actin-nucleotide exchange rate and the Kd for rabbit skeletal actin. This recombinant material crystallized from 80% saturated sodium potassium tartrate, yielding monoclinic crystals, space group C2, a = 91.4 A, b = 37.4 A, c = 34.7 A, beta = 109.6 degrees. These crystals contain one molecule in the asymmetric unit and diffract to 2.0 A.