BIOB10H3 Lecture Notes - Lecture 10: Atp Hydrolysis, Depolymerization, Polymerization
Document Summary
They are smaller compared to 25nm microtubules: monomer that builds actin filaments is called g-actin =globular actin, polymerizes into f-actin =filamentous actin/microfilament, f-actin polymers assemble into a double helix. Microfilaments have polarity: (-) end: pointed end (+) end: barbed end. Depolymerization of f-actin: can occur at either end when concentrations of monomers are high, when concentrations are low depolymerization occurs preferentially at the (-) end or pointed end, actin is constantly assembling and disassembling. Assembly and disassembly: when monomer concentrations are high the assembly and disassembly at the (+) and (-) end are equal. You are studying 2 proteins that you suspect cap the ends of actin filaments. By examining the graphs below, predict which protein caps the plus end and which protein caps the minus end. In general monomers are added to the (+) end and in graph (c) monomer concentrations are built up and only a small amount of filament is being made.
