December 10, 2003Proceedings of the National Academy of Sciences125 citationsOpen Access

Donation of catalytic residues to RNA polymerase active center by transcription factor Gre

ESEkaterina SosunovaCentral Scientific Research Institute of Tuberculosis Russian Academy of Medical Sciences VSVasily SosunovCentral Scientific Research Institute of Tuberculosis Russian Academy of Medical Sciences МКМ. В. КозловEngelhardt Institute of Molecular Biology

Key Points

Key points are not available for this paper at this time.

Abstract

During transcription elongation, RNA polymerase (RNAP) occasionally loses its grip on the growing RNA end and backtracks on the DNA template. Prokaryotic Gre factors rescue the backtracked ternary elongating complex through stimulation of an intrinsic endonuclease activity, which removes the disengaged 3' RNA segment. By using RNA-protein crosslinking in defined ternary elongating complexes, site-directed mutagenesis, discriminative biochemical assays, and docking of the two protein structures, we show that Gre acts by providing two carboxylate residues for coordination of catalytic Mg2+ ion in the RNAP active center. A similar mechanism is suggested for the functionally analogous eukaryotic SII factor. The results expand the general two-metal model of RNAP catalytic mechanism whereby one of the Mg2+ ions is permanently retained, whereas the other is recruited ad hoc by an auxiliary factor.

Ask AI

Helpful

Bookmark

View Full Paper