Kühlmann U C, Kleanthous C, James R, Moore G R, Hemmings A M
School of Chemical Sciences, University of East Anglia, Norwich NR4 7TJ, England.
Acta Crystallogr D Biol Crystallogr. 1999 Jan;55(Pt 1):256-9. doi: 10.1107/S0108444998002590. Epub 1999 Jan 1.
We have crystallized and performed preliminary X-ray characterization of the complex between the DNAase domain of the E9 colicin and its cognate immunity protein Im9. The dissociation constant for this complex, Kd = 1 x 10(-16) M, reveals it to be one of the highest affinity protein-protein interactions known. Single crystals of the 1:1 complex were grown from microseeding experiments using PEG 4K as precipitant. The space group is P212121 with one molecule of complex in the asymmetric unit, and crystals contain approximately 43% solvent. These crystals are inherently non-isomorphous and so selenomethionine-derivatized protein has been prepared and crystals grown for MAD phasing experiments.
