Expression, purification, crystallization and preliminary X-ray diffraction analysis of the novel modular DNA-binding protein BurrH in its apo form and in complex with its target DNA.

Abstract

Different genome-editing strategies have fuelled the development of new DNA-targeting molecular tools allowing precise gene modifications. Here, the expression, purification, crystallization and preliminary X-ray diffraction of BurrH, a novel DNA-binding protein from Burkholderia rhizoxinica, are reported. Crystallization experiments of BurrH in its apo form and in complex with its target DNA yielded crystals suitable for X-ray diffraction analysis. The crystals of the apo form belonged to the primitive hexagonal space group P3(1) or its enantiomorph P3(2), with unit-cell parameters a = b = 73.28, c = 268.02 Å, α = β = 90, γ = 120°. The BurrH-DNA complex crystallized in the monoclinic space group P2(1), with unit-cell parameters a = 70.15, b = 95.83, c = 76.41 Å, α = γ = 90, β = 109.51°. The self-rotation function and the Matthews coefficient suggested the presence of two protein molecules per asymmetric unit in the apo crystals and one protein-DNA complex in the monoclinic crystals. The crystals diffracted to resolution limits of 2.21 and 2.65 Å, respectively, using synchrotron radiation.