JBC, Vol. 252, Issue 24, 9024-9031, Dec, 1977
Reconstitution studies show that rifampicin resistance is determined by the largest polypeptide of Bacillus subtilis RNA polymerase
S. M. Halling, K. C. Burtis and R. H. Doi
A procedure has been developed to separate the subunits of Bacillus
subtilis RNA polymerase rapidly and in good yield. The method involved the
use of a blue dextran-Sepharose column which bound the beta' subunit. A
phosphocellulose column was used to separate the alpha and beta subunits.
During purification, the enzyme eluted from the DNA-cellulose column in
three separate forms in the order
alpha2betabeta'deltaomega1,alpha2betabeta'omega1, and
alpha2betabeta'omega1sigma. Subunit reconstitution studies with RNA
polymerase subunits from wild type and a rifampicin-resistant mutant
indicated that the largest polypeptide was responsible for rifampicin
resistance. Thus, this subunit is referred to as beta. The mobility of the
subunits in sodium dodecyl sulfate-polyacrylamide gel electrophoresis
cannot be used as the sole criterion for designating the functions of the
subunits of RNA polymerase.