CROSS-LINKING OF BETA-HEAVY-CHAIN SUBUNIT OF DYNEIN FROM SEA-URCHIN SPERM FLAGELLA BY DIMETHYL SUBERIMIDATE

The dynein beta heavy chain and the intermediate chain 1 (IC1) from se a urchin sperm flagella cosediment at 11S through sucrose density grad ient centrifugation. When the isolated beta/IC1 complex was treated wi th a bifunctional cross-linker, dimethyl suberimidate (DMS), and analy zed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, four high molecular mass products appeared on the gel. Immunoblotting of t he products with affinity-purified polyclonal antibodies against beta heavy chain and IC1 revealed that these were cross-linked products of beta heavy chain and IC1. Treatment of beta/IC1 complex with DMS activ ated the ATP hydrolysis and decreased its sensitivity to inhibition by vanadate. These results indicate the dynein beta heavy chain and IC1 associate with each other to form a complex and suggest that the intra molecular interactions within beta/IC1 complex are involved in the pro cess of ATP hydrolysis.