ABSTRACT
Proteins move and transform matter on a molecular scale in biosystems. Proteins constitute the molecular machines that enable life processes to take place. Machines that transform matter are usually called enzymes, and the transport machines are called motors. Molecular motors comprise a class of molecular machines whose primary function is to transport objects along a track. The Brownian ratchet was publicized by Richard Feyman in lectures given to introductory physics classes at the California Institute of Technology. In biochemical reactions in which adenosine triphosphate (ATP) is converted to ADP, the issue of “coupling” of ATP hydrolysis to some other process is often said to be an issue. Rotational motors that drive whole cells through water with no tracks, like the flagella of bacteria, can also be directional. Deoxyribonucleic acids (DNA) processing enzymes such as gyrases, ribonucleic acids polymerase, topoisomerases, helicases, and the nucleosome all cause some degree of twisting or writhing of the B-DNA helix.
