The first human breast and ovarian cancer susceptibility protein (BRCA1) is a tumour suppressor with an N-terminal RING domain and two tandem BRCA1 C-terminal (BRCT) domains. Although the structures of the two evolutionarily conserved termini have been solved, the structure of the poorly conserved central region remains unknown. To investigate this central portion, twenty-one overlapping protein fragments were designed to collectively encompass the central region. The structures of the soluble and intact fragments were characterized with nuclear magnetic resonance spectroscopy, circular dichroism spectroscopy and limited trypsin proteolysis. All of the protein fragments assayed appeared to be largely disordered. Gel electrophoretic mobility shift assays revealed that six of the fragments bound DNA, allowing the mapping of the published DNA binding region to a higher resolution. The lack of structure in the central region supports a model in which BRCA1 acts as a scaffolding protein for interactions with signalling proteins and DNA.