RIFAMYCINS - RELATION OF CHEMICAL STRUCTURE AND ACTION ON RNA POLYMERASE

The interaction of RNA polymerase with various rifamycin derivatives has been studied. It could be shown that the macrocyclic ring is the part of the molecule responsible for the complex formation and inhibition of RNA polymerase. Very slight modifications, such as oxidation in the case of rifamycin Y or hydrogenation of double bonds, alter the sterical shape of the ring in such a way that it no longer shows optimal binding to the acceptor site of the enzyme. Changes in other parts of the molecule have little effect on the direct action on RNA polymerase but may affect the permeation into intact bacterial cells. © 1969.