ACTIN DYSTROPHIN INTERFACE

Dystrophin, an elongated cytoskeletal molecule which is deficient in D uchenne muscular disease, contains an actin-binding domain in its N-te rminal portion. We show that this part interacted with actin in the na tive molecule. By molecular biology techniques, four recombinant prote ins were expressed in Escherichia coli using the pMAL vector which all owed us to obtain soluble proteins directly after purification. These constructions were tested for their ability to bind actin under variou s conditions, and their apparent dissociation constants were determine d. The effects of other actin-binding proteins such as caldesmon and t ropomyosin were analyzed in comparison to the actin-binding properties of these constructions. These results support the potential concept o f a multiple actin-binding contact in the N-terminal region of dystrop hin. Differences in the functional domains are discussed relative to s imilar alpha-actinin-actin-binding sites.