Expression, purification and preliminary crystallographic studies of a single-point mutant of Mos1 mariner transposase.

A soluble single-point mutant of full-length Mos1 mariner transposase (MW = 40.7 kDa) has been overexpressed in Escherichia coli, purified to 95% homogeneity and crystallized. This provides the first example of the crystallization of a eukaryotic transposase. The native crystals diffract to 2.5 A resolution and show tetragonal symmetry, with unit-cell parameters a = b = 44.5, c = 205.6 A. Multiple-wavelength anomalous data from a selenomethionyl form of the protein and data from a heavy-atom derivative have been collected.