PSL300H1 Lecture Notes - Ryanodine, Troponin, Ford Power Stroke Engine
Document Summary
Some physically joined sr channel opened. Ca2+ itself binds to sr ca2+ channels by t channel triggers conformational change ca2+ moves to sarcoplasm: net ca2+ from sr into sarcoplasm sliding filament mech. 35-36nm apart: when ca2+ in sarcoplasm when act pot arrives binds to troponin, now myosin can, contract"n can physically bind occur. Cross-bridge formation: myosin head f"ns as atpase when bound to actin. Irony: breakdown of atp already taken place before binding myosin head storing elastic energy, has pi & adp still bound: when ca2+ bound to troponin myosin attaches to actin. Phosphate released, leaving adp bound to myosin head. ~10nm releases stored energy: adp replaced w fresh. Atp immediately broken down bond w actin broken myosin head energized, pushed back to original position: can"t go again until comes to binding site. Myosin reattachmen t: myosin head can"t reattach to actin til is opposite a binding site binding sites 35-36nm apart, distance btwn adjacent myosin heads =
