9 Rifampicin is known to inhibit RNA synthesis in E. coli. Once the first ten nucleotides
have been incorporated, rifampicin does not inhibit RNA synthesis. Which of the
following best explains how rifampicin functions?
(A)rifampicin binds only to the core enzyme when bound to DNA but can bind to the
holoenzyme when not bound to DNA
(B) rifampicin can bind to RNA polymerase when the polymerase is not bound to DNA but
cannot bind when the polymerase is bound to DNA
(C) rifampicin only inhibits when the a subunit is bound to the core enzyme
(D) rifampicin is able to bind to the nucleotide binding site at any time
(E) none of the above