ATP-dependent conformational changes of dynein: evidence for changes in the interaction of dynein heavy chain with the intermediate chain 1.

Conformational changes of the dynein beta heavy chain/intermediate chain 1 (IC1) complex from outer arm dynein of sea urchin sperm flagella were examined by means of cross-linking experiments using a bifunctional cross-linker, dimethylsuberimidate. Cross-linking of the beta/IC1 complex in the absence of ATP and vanadate (Vi) produced five cross-linked products. Immunoblotting of the products with anti-beta chain and anti-IC1 antibodies revealed that all of them were cross-linked between beta chain and IC1. Cross-linking of the complex in the presence of ATP and Vi produced four cross-linked products, but their electrophoretic mobilities were different from those of the cross-linked products obtained in the absence of ATP and Vi. Immunoblotting showed that only one cross-linked product was formed by cross-linking between beta and IC1 and others were formed by intramolecular cross-linking of the beta chain. Quantitative analysis indicated that cross-linking between beta and IC1 decreased in the presence of ATP and Vi. These results suggest that conformational changes of the beta heavy chain occur and the interaction between beta chain and IC1 changes during ATP hydrolysis.