copying machine

Despite extensive research, the molecular mechanism by which epigenetic information is passed down through the DNA copying machine, called the replisome, remains unclear.

Researchers from Göttingen and Hannover have now succeeded for the first time in visualising the copying machine of chloroplasts, the RNA polymerase PEP, in high-resolution 3D.

Not only the copying process is complex, but also the copying machine itself: It consists of a multi-subunit core complex, whose protein parts are encoded in the chloroplast genome, and at least twelve associated proteins, called PAPs.

"So far, we have been able to characterise some individual parts of the chloroplast copying machine structurally and biochemically, but we lacked a precise insight into its overall structure and the functions of the individual PAPs," says Prof. Dr. Thomas Pfannschmidt, professor at the Institute of Botany at Leibniz University Hannover.

The researchers then photographed the copying machine thousands of times and down to the atomic level from numerous angles and combined them into an overall image using complicated computer calculations.