Solution Structure of the Activator Contact Domain of the RNA Polymerase α Subunit

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Science  01 Dec 1995:
Vol. 270, Issue 5241, pp. 1495-1497
DOI: 10.1126/science.270.5241.1495


The structure of the carboxyl-terminal domain of the Escherichia coli RNA polymerase α subunit (αCTD), which is regarded as the contact site for transcription activator proteins and for the promoter UP element, was determined by nuclear magnetic resonance spectroscopy. Its compact structure of four helices and two long arms enclosing its hydrophobic core shows a folding topology distinct from those of other DNA-binding proteins. The UP element binding site was found on the surface comprising helix 1, the amino-terminal end of helix 4, and the preceding loop. Mutation experiments indicated that the contact sites for transcription activator proteins are also on the same surface.