CONFORMATIONAL-CHANGES OF THE BETA-CHAIN OF THE OUTER-ARM DYNEIN FROM SEA-URCHIN SPERM FLAGELLA COUPLED WITH ATP HYDROLYSIS

Conformational changes of the β chain of the outer-arm dynein from sea urchin sperm flagella in relation to ATP hydrolysis was examined by tryptic digestion. Tryptic digestion of the β chain in the presence of 2 mM ATP (ADP) and 100 μM vanadate (V1) or in the presence of 4 mM ATPγS produced different polypeptides from in the case of no addition. The difference was similar to the result previously reported for 21S outer-arm dynein heavy chains [Inaba, K. & Mohri, H. (1989) J. Biol. Chem. 264, 8384-8388]. Unlike the tryptic digestion pattern of 21S dynein heavy chains, however, the 135-kDa polypeptide was consistently produced from the β chain, even in the presence of ATP (ADP) and V1. The tryptic digestion pattern of the 21S particle reconstituted from the separated α chain, the β/ IC1 complex and the IC2/IC3 complex [Tang, W.-J.Y., Bell, C.W., Sale, W.S., & Gibbons, I.R. (1982) J. Biol. Chem. 257, 508-515] was similar to that of intact 21S dynein; the 135-kDa polypeptide was only slightly produced in the presence of ATP and V1. The digestion rate constant of the 135-kDa polypeptide from the β chain in the presence of ATP and V1 was significantly decreased as compared with in the case of 21S dynein or that of the reconstituted 21S particle. These results suggest that the trypsin sensitivity of the 135-kDa region of the β chain changes with the association of the β/IC1 complex with the α chain and the IC2/ IC3 complex in the presence of ATP and V1. © 1990 Copyright, 1990 by the Journal of Biochemistry.