Proteolytic Fragments of Connectin Cause Aggregation of Myosin Filaments but not of Actin Filaments1

Abstract

Proteolytic fragments of 400 kD isolated from chymotrypsin-treated connection, a muscle elastic protein, still retained the ability to cause aggregation of myosin filaments but lost the actin-bundling action. Tryptic digests of connectin showed similar effects. However, when connection was hydrolyzed by pepsin to peptides smaller than approximately 40 kD, no such action was seen for both myosin and actin filaments. It is suggested that the actin bundling action of connectin filaments is due to topological restrictions. A modified reproducible procedure for the preparation of native connectin from chicken breast muscle is described in detail.