Myosin II presents two fragments;
light meromyosin (LMM), which corresponds to two thirds of the tail and is responsible for the self-assembly of protein dimers, and heavy meromyosin (HMM), that is divided in two subfragments; the subfragment 1 (S1), which includes the motor domain, is consisted of globular heads, and the subfragment 2 (S2), which corresponds to the proximal third of the tail and acts as flexible connection between S1 and LMM (Craig & Woodhead, 2006).