Question

Describe how a motor protein uses ATP hydrolysis to convert chemical energy into motion. i.e. What is the mechanism common to all motor proteins. How does this differ from the synthesis of ATP on the F₁F₀ ATP synthase?

Answer 1

Motor protein are a class of molecular motors that can move along the cytoplasm of animal cells. They convert chemical energy into mechanical work by the hydrolysis of ATP. Flagellar rotation, however, is powered by a proton pump.

Motor proteins are molecular motors that use ATP hydrolysis to move along cytoskeletal filaments within the cell. Members of two large families of motor proteins the kinesins and dyneins are responsible for powering the variety of movements in which microtubules participate.

The ability of ATP powered motor proteins to convert chemical free energy into the mechanical work required to move intra cellular organelles is discussed in terms of the molecular and dynamic fundamentals involved in producing such movements. This is carried out in detail for muscle contraction with the result that in order for a myosin head to act as a motor protein,it is necessary for it to be able to impose a unique series of impacts on an actin filament.

ATP synthesis by oxidation phosphorylation and photophosphorylation, catalysed by F1F0 ATP synthesis, is the fundamental means of cells energy production. Earlier mutagenesis studies had gone some way to describing the mechanism. More recently, several X-rays structures at atomic resolution have pictured the catalytic site, and real-time video recordings of subunit rotation have left no doubt of the nature of energy coupling between the transmembrane proton gradient and the catalytic sites in this extraordinary molecular motor. Nonetheless, the molecular events that are required to accomplish the chemical synthesis of ATP remain undefined.

summery: F1F0 ATP synthesis are multimeric protein complexes and common prerequisites for their correct assembly are 1. provision of subunits in appropriate relative amount 2. coordination of membrane insertion and 3. avoidance of assembly intermediates that uncouple the proton gradient or wastefully hydrolyse ATP.