The Escherichia coli rpoB gene, which codes for the 1342-residue β subunit of RNA polymerase (RNAP), contains two dispensable regions centered around codons 300 and 1000. To test whether these regions demarcate domains of the RNAP β subunit, fragments encoded by segments of rpoB flanking the dispensable regions were individually overexpressed and purified. We show that these β-subunit polypeptide fragments, when added with purified recombinant β', σ, and α subunits of RNAP, reconstitute a functional enzyme in vitro. These results demonstrate that the β subunit is composed of at least three distinct domains and open another avenue for in vitro studies of RNAP assembly and structure.
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - 9 May 1995|