How Myosin Generates Force on Actin Filaments Anne Houdusse, H. Lee Sweeney  Trends in Biochemical Sciences  Volume 41, Issue 12, Pages 989-997 (December 2016) DOI: 10.1016/j.tibs.2016.09.006 Copyright © 2016 Elsevier Ltd Terms and Conditions

Figure 1 Key Figure: Myosin Force Generation on Actin Filaments Several structural states of the motor allow this molecular machine to generate force upon ATP hydrolysis. This scheme provides a unifying view of the current available structural and functional data available for this motor. The myosin heads are shown in red for states of the motor that produce force. This cycle describes the structural transitions during the powerstroke that actin promotes in the motor to sequentially release the hydrolysis products while directing a nanometer-long conformational change in the lever arm coupled to the swing of the converter (green). Trends in Biochemical Sciences 2016 41, 989-997DOI: (10.1016/j.tibs.2016.09.006) Copyright © 2016 Elsevier Ltd Terms and Conditions

Figure 2 Myosin Motor Domain. A ribbon diagram of the myosin V motor illustrates components of the myosin motor domain, including the four subdomains (U50, L50, N-term., and converter) that move relative to each other during the structural transitions of the myosin force-generating cycle on actin. The subdomains are linked by flexible connectors (Switch II, Relay, SH1 helix, and strut). ATP is bound to the switch elements (Switch I and Switch II) and P-loop of the active site. The actin-binding site comprises actin-binding loops (such as the HCM loop and activation loop) from both the upper (U50) and lower (L50) 50-KDa subdomains that are separated by the actin-binding cleft, as well as a helix–loop–helix region of the lower 50-KDa (L50) subdomain. The Switch II connector (orange), situated close to the position where the γ-phosphate of ATP is bound, is found at the other end of this actin-binding cleft compared with the actin-binding site. The central beta sheet has a critical role in closing the cleft during the powerstroke on actin and is part of the transducer region (cyan). A switch II (orange) movement creates a tunnel to release phosphate at the beginning of the powerstroke. Trends in Biochemical Sciences 2016 41, 989-997DOI: (10.1016/j.tibs.2016.09.006) Copyright © 2016 Elsevier Ltd Terms and Conditions