Single-Molecule Measurements Using Microneedles

Myosin is both an enzyme and a molecular motor that hydrolyzes ATP and interacts with actin filaments for force generation. Manipulation techniques with microneedles and laser traps have recently been developed to capture and manipulate the actomyosin interaction for the purpose of revealing the mechanics of this system. Combined with single-molecule imaging techniques, the coupling between chemical processes (ATP hydrolysis) and mechanical processes (myosin force generation) has been directly determined. In this chapter, we describe these two manipulation techniques, especially microneedle method, in detail.