We have used a nonspecific protein cleaving reagent to map the interactions between subunits of the multisubunit enzyme RNA polymerase (Escherichia coli). We developed suitable conditions for using an untethered Fe-EDTA reagent, which does not bind significantly to proteins. Comparison of the cleaved fragments of the subunits from the core enzyme (α2ββ′) and the holoenzyme (core + σ70) shows that absence of the σ70 subunit is associated with the appearance of several cleavage sites on the subunits β (within 10 residues of sequence positions 745, 764, 795, and 812) and β′ (within 10 residues of sequence positions 581, 613, and 728). A cleavage site near β residue 604 is present in the holoenzyme but absent in the core, demonstrating that a conformational change occurs when σ70 binds. No differences are observed for the α subunit.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jan 9 1996|
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