Department of Molecular and Cellular Interactions, Vlaams Interinuversitair Instituut voor Biotechnologie and Laboratorium voor Ultrastructuur, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussel, Belgium.
CcdA and CcdB are the antidote and toxin of the ccd addiction module of Escherichia coli plasmid F. The CcdA C-terminal domain (CcdAC36; 36 amino acids) was crystallized in complex with CcdB (dimer of 2 x 101 amino acids) in three different crystal forms, two of which diffract to high resolution. Form II belongs to space group P2(1)2(1)2(1), with unit-cell parameters a = 37.6, b = 60.5, c = 83.8 A and diffracts to 1.8 A resolution. Form III belongs to space group P2(1), with unit-cell parameters a = 41.0, b = 37.9, c = 69.6 A, beta = 96.9 degrees, and diffracts to 1.9 A resolution.