Roger Kornberg, a structural biologist at Stanford University, and his collaborators first decoded the structure of RNAP in 2001, earning him the 2006 Nobel Prize in Chemistry.
So, molecular motors such as RNAP could work like microscopic Maxwell demons, using energy to select favorable fluctuations of energy when opportunities arise.
When they decoded RNAP's structure, Kornberg and his team discovered that RNAP includes a system of two moving parts, located next to the site within RNAP where new RNA bases bind to the DNA template.
Indeed, in 2005, Nudler and his collaborators showed that mutations altering the trigger structure rendered the RNAP unable to move preferentially forward.
Block's team measured the pull exerted by single RNAP molecules during the transcription process.