Optical tweezers have become an integral tool for studying the mechanochemical cycle of kinesin and myosin. Recently, the technological advances developed to study these motor proteins have been applied to the study of processive nucleic enzymes, in particular RNA and DNA polymerase. One difficulty with measuring DNA-based motors is the large compliance corrections associated with the entropic elasticity of DNA. A second difficulty is their slow speed. For comparison, kinesin moves at 800 nm/s whereas RNA polymerase moves at ~4 nm/s. Our research has focused on processive nucleic acid enzymes, some of which depend on ATP hydrolysis, RecBCD, and some of which do not, lambda exonuclease