J. Biochem, 1994, Vol. 115, No. 2 351-355
© 1994 Japanese Biochemical Society
research-article |
Purification and Characterization of the 1, 200-kDa Subfragment of Connectin Filaments Produced by 0.1 mM Calcium Ions1
Meat Science Laboratory, Department of Animal Science, Faculty of Agriculture, Hokkaido University Kita-ku, Sapporo, Hokkaido 060
3 To whom correspondence should be addressed.
When myofibrils prepared from chicken leg muscle were treated with a solution containing 0.1 mM CaCl2 and 30 µg/ml of leupeptin,
-connectin, which exists as a longitudinal thin filament in a sarcomere, was split into ß-connectin and
1, 200-kDa subfragment. The native subfragment was successfully purified without using any denaturant: It was extracted with 1 M KI solution from the Ca-treated myofibrils and purified by TSKge1 G6000PW column chromatography. About 10 mg of the subfragment was yielded from 100 g of starting muscle. Using immunofluorescence microscopy and immunoelectron microscopy, we show here that polyclonal antibodies against the 1, 200-kDa subfragment bind to the Z-disk and the epitope, which is about 0.34 um apart from the Z-disk at a sarcomere length of 2.6 µm; the 1, 200-kDa subfragment constitutes the proximal region of connectin filaments. Purified
-actinin decorated
-connectin and the 1, 200-kDa subfragment on nitrocellulose blots of myofibrillar proteins separated by SDS-PAGE. Therefore, we conclude that connectin filaments are anchored to the Z-disk by the binding of the 1, 200-kDa subfragment to
-actinin.
1This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan.
2Present address: Department of Animal Products, National Institute of Animal Industry, 2 Ikenodai, Kukizaki-cho, Inashiki-gun, Ibaraki 305.