The evolving story of AtzT, a periplasmic binding protein
The structure of AtzT, which is thought to be involved in atrazine uptake in bacteria, was solved by SAD phasing using an ethylmercury phosphate derivative. Density in the binding site was subsequently found to be guanine that was retained by the protein throughout the purification process. Replacing the guanine with 2-hydroxyatrazine allowed the manner of binding of this substrate to be determined and its comparison with what appears to be the original ligand for this protein.