Crystallization and preliminary X-ray crystallographic studies of Mycobacterium tuberculosis CRP/FNR family transcription regulator

Abstract

CRP/FNR family members are transcription factors that regulate the transcription of many genes in Escherichia coli and other organisms. Mycobacterium tuberculosis H37Rv contains a probable CRP/FNR homologue encoded by the open reading frame Rv3676. The deletion of this gene is known to cause growth defects in cell culture, in bone marrow-derived macrophages and in a mouse model of tuberculosis. The mycobacterial gene Rv3676 shares approximately 32% sequence identity with prototype E. coli CRP. The structure of the protein might provide insight into transcriptional regulation in the pathogen by this protein. The M. tuberculosis CRP/FNR transcription regulator was crystallized in space group P2(1)2(1)2(1), with unit-cell parameters a = 54.1, b = 84.6, c = 101.2 A. The crystal diffracted to a resolution of 2.9 A. Matthews coefficient and self-rotation function calculations reveal the presence of two monomers in the asymmetric unit.

Figure 1

Crystals of CRP/FNR transcription factor grown using 15% ethanol, 0.2 M Li₂SO₄ and 0.1 M sodium phosphate citrate pH 5.5. The size of each crystal is approximately 0.1 × 0.15 × 0.1 mm.