Background: The PDZ-LIM proteins are a family of signalling adaptors that interact with the actin cross-linking protein, α-actinin, via their PDZ domains or via internal regions between the PDZ and LIM domains. Three of the PDZ-LIM proteins have a conserved 26-residue ZM motif in the internal region, but the structure of the internal region is unknown.

Earlier reports have shown that ALP has an internal interaction site. We were able to stabilize the structure of this unfolded part to a great extent by aspartic acid, which allowed the backbone assignment. No secondary structure of the polypeptide was observed.