 |
| Previous Image | Next Image |
| Description: Left: Relaxed muscle. At low Ca+2 levels, the configuration of actin, tropomyosin, and the troponin complex in the thin filament blocks most myosin headpieces from contacting the thin filament. Right: The binding of Ca+2 to TnC opens a binding site on TnC for the inhibitory domain of TnI, which also binds actin (see left panel). The release of TnI from actin allows the tropomyosin–troponin complex to slide closer to the central groove in F-actin, therby exposing the myosin-binding site. Cross-bridge formation can then occur, and the muscle contracts. Picture Stats: Views: 272 Filesize: 164.79kB Height: 410 Width: 811 Source: https://biology-forums.com/index.php?action=gallery;sa=view;id=34159 |