J. Biol. Chem., Vol. 266, Issue 5, 2911-2916, Feb, 1991
Identification and characterization of RNA polymerase sigma factor from Micrococcus luteus
M Nakayama, N Fujita, S Osawa and A Ishihama
Department of Molecular Genetics, National Institute of Genetics, Shizuoka, Japan.
The promoters of Micrococcus luteus, a bacterium whose chromosomal DNA has
a high G + C content (74%), diverge from the consensus prokaryotic promoter
in having GC-rich DNA sequences at less important positions (Nakayama, M.,
Fujita, N., Ohama, T., Osawa, S., and Ishihama, A. (1989) Mol. Gen. Genet.
218, 384-389). In order to compare the promoter selectivity of RNA
polymerase between M. luteus and Escherichia coli, we purified the enzyme
from both organisms. The sets of promoters recognized by the two RNA
polymerases were found to overlap partly. Some, but not all, E. coli
promoters were found to be correctly transcribed in vitro by M. luteus RNA
polymerase as well as the E. coli enzyme. One molecular species of M.
luteus sigma factor, with the apparent molecular mass of 60 kDa, was
isolated from purified RNA polymerase. By the addition of either M. luteus
or E. coli core enzyme it was reconstituted into active holoenzyme.
Likewise, M. luteus core enzyme was reconstituted into a hybrid holoenzyme
by the addition of E. coli sigma subunit. Both hybrid holoenzymes were,
however, able to initiate transcription only from promoters which were
recognized by both of the native holoenzymes.
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