Crystallization of redox-insensitive Oct1 POU domain with different DNA-response elements

The POU domain of the human Oct1 transcription factor has been crystallized with two different POU-dimer-binding DNA elements. Protein-DNA cocrystals suitable for structural analysis could be obtained only with a redox-insensitive version of the POU domain. The recombinant protein expression in a prokaryotic host was adjusted for fast purification. Optimized crystals were obtained by systematically varying the length of the oligonucleotide and by modifying cryofreezing procedures. These steps are generally applicable to the preparation of protein-DNA complexes for structural studies.