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Publication Abstract from PubMed

NusA is a key regulator of bacterial transcriptional elongation, pausing, termination and antitermination, yet relatively little is known about the molecular basis of its activity in these fundamental processes. In Mycobacterium tuberculosis, NusA has been shown to bind with high affinity and specificity to BoxB-BoxA-BoxC antitermination sequences within the leader region of the single ribosomal RNA (rRNA) operon. We have determined high-resolution X-ray structures of a complex of NusA with two short oligo-ribonucleotides derived from the BoxC stem-loop motif and have characterised the interaction of NusA with a variety of RNAs derived from the antitermination region. These structures reveal the RNA bound in an extended conformation to a large interacting surface on both KH domains. Combining structural data with observed spectral and calorimetric changes, we now show that NusA binding destabilises secondary structure within rRNA antitermination sequences and propose a model where NusA functions as a chaperone for nascently forming RNA structures.

Structure of a Mycobacterium tuberculosis NusA-RNA complex.,Beuth B, Pennell S, Arnvig KB, Martin SR, Taylor IA EMBO J. 2005 Oct 19;24(20):3576-87. Epub 2005 Sep 29. PMID:16193062^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.