discovered a new cytoskeletal polymer that resembles actin in an archaean; you call the subunit for this polymer AALP (for archaea actin-like protein). AALP binds to ATP and can catalyze the hydrolysis of ATP to ADP. As with actin, this hydrolysis occurs more quickly when AALP is in a filament and most of the free AALP is bound to ATP. You measure the rate of AALP filament growth in vitro at the plus (more quickly growing) end and at the minus (more slowly growing) end and obtain the graph diagrammed in the figure