Distribution of troponin components in the thin filament studied by immunoelectron microscopy.

1. The localization of specific antiboidies against troponin components, i.e., troponin T(TN-T), troponin I(TN-I, and troponin C(TN-C), was studied by the use of an electrom microscope. 2. Every antibody was distributed along the thin filament with a period of 38 nm. 3. Staining with anti-TN-I or anti-TN-C formed narrow striations. The location of the first striation was 26 nm from the free end of the thin filament. 4. The width of individual striations formed by anti-TN-T was 14--20nm The H-band-side end of each striation coincided with the location of anti-TN-I or anti-TN-C.