Structural studies of the Msx-1 homeodomain-DNA complex I

Crystals of the Msx-1 homeodomain-DNA complex have been obtained by hanging -drop vapor diffusion at 293 K in 12% PEG 4000 and 0.1 M sodium acetate pH 4.6. The homeodomain consists of 60 amino acids and is the DNA-binding doma in. The DNA in the complex was 16 base pairs with the sequence 5'-TGTCACTAA TTGAAGG-3', containing an overhang T at each end. The crystals diffract to 2.15 Angstrom (99.8% completeness) using cryogenic (123 K) conditions. The crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-ce ll parameters a = 33.66, b = 60.96, c = 83.37 Angstrom. The structure will illuminate the details of Msx-1-DNA binding specificity and clarify its rol e in transcriptional regulation. Mutations in Msx-1 cause craniofacial defo rmities in mice.