Skip Navigation

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Request Permissions
Google Scholar
Right arrow Articles by Ohashi, K.
Right arrow Articles by Maruyama, K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ohashi, K.
Right arrow Articles by Maruyama, K.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

J. Biochem, 1989, Vol. 106, No. 1 104-109
© 1989 Japanese Biochemical Society

research-article

I-Protein Forms Cage-Like Aggregates of Myosin In Vitro1

Kazuyo Ohashi, Kensuke Ishikawa and Koscak Maruyama

Department of Biology, Faculty of Science, Chiba University Chiba, Chiba 260

I-protein was mixed with myosin before or after myosin filaments were reconstituted. In both cases, I-protein seemed to accelerate the myosin assembly. The binding of I-protein to myosin filaments was tested by sedimentation experiments and SDS-polyacrylamide gel electrophoresis. In a low ionic strength solution at pH 6.5, the binding ratio of I-protein to myosin was 1: 40 by molar ratio when the I-protein molecules highly specifically bound to myosin filaments. I-protein could maximally bind to myosin filaments at the molar ratio of 1: 2.7. In this case, excess I-protein molecules remained in the supernatant after sedimentation, although the unbound I-protein could still bind to myosin filaments. Electron microscopic observations revealed that I-protein bundled myosin filaments in the low ionic strength solution (pH6.5). Cage-like structures which were very similar to the Mg-paracrystals of non-muscle myosins were formed at pH 7.2. In gel filtration, the apparent molecular mass of I-protein was 100 kDa, while it was 50 kDa in SDS gel electrophoresis. Therefore, I-protein is regarded to be a homodimer of a 50 kDa subunit and can divalently bind to myosin molecules.

1This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.