Patrick Cramer studies the molecular machinery of transcription: how RNA polymerases copy information from DNA into RNA. His work connects the three-dimensional structures of these enzymes with the steps by which they add nucleotides and advance along a template. [ref]
With Florian Brueckner, Cramer used alpha-amanitin to trap a possible intermediate in the movement of RNA polymerase II. A structure at 3.4 angstrom resolution showed a shifted RNA polymerase bridge helix and a particular position of the RNA polymerase trigger loop.[ref]
Structural basis of transcription inhibition by alpha-amanitin and implications for RNA polymerase II translocation by Florian Brueckner and Patrick Cramer. abstract, inhibitor-soaked crystals and structural interpretation
A useful way to understand this strategy is to distinguish an enzyme's chemical reaction from its mechanical reset: after extending an RNA chain, the machinery must position the next template base. Trapping different arrangements can reveal how those tasks are coordinated. A trapped structure is a snapshot under experimental conditions, however, so assigning it to the normal reaction cycle also requires biochemical evidence.
Patrick Cramer
. Portrait identified on his Max Planck Society profile. New to topics? Read the docs here!