RNA binding proteins control gene expression by the attenuation/antitermination mechanism. HutP is an RNA binding antitermination protein. It regulates the expression of hut operon when it binds with RNA by modulating the secondary structure of single-stranded hut mRNA. HutP necessitates the presence of L-histidine and divalent metal ion to bind with RNA. Herein, we report the crystal structures of ternary complex (HutP-L-histidine-Mg2+) and EDTA (0.5 M) treated ternary complex (HutP-L-histidine-Mg2+), solved at 1.9 angstrom and 2.5 angstrom resolutions, respectively, from Geobacillus thermodenitrificans. The addition of 0.5 M EDTA does not affect the overall metal-ion mediated ternary complex structure and however, the metal ions at the non-specific binding sites are chelated, as evidenced from the results of structural features. (C) 2014 Elsevier Inc. All rights reserved.