NTP-entry routes in multi-subunit RNA polymerases
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Updated: Aug 13, 2026

High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
1Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA. landick@bact.wisc.edu
Abstract:
The recent elucidation of crystal structures for multi-subunit RNA polymerases immediately revealed a mystery: how do nucleotide triphosphate (NTP) substrates reach an active site that is buried deep within the enzyme? The prevailing view is that NTPs enter through an approximately 20A-long secondary channel between the active site and the enzyme surface. Recently, an alternative view has been advocated; namely, NTPs enter the active site pre-bound to the DNA template from the downstream DNA portion of the main channel of the enzyme.
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