2ASB

Structure of a Mycobacterium tuberculosis NusA-RNA complex

Summary for 2ASB

• Entry DOI: 10.2210/pdb2asb/pdb
• Related: 2ATW
• Descriptor: ribosomal RNA (5'- GAACUCAAUAG -3'), Transcription elongation protein nusA (3 entities in total)
• Functional Keywords: protein-rna complex, transcription-rna complex, transcription/rna
• Biological source: Mycobacterium tuberculosis; More
• Total number of polymer chains: 2
• Total formula weight: 30525.82

Authors

Beuth, B.,Pennell, S.,Arnvig, K.B.,Martin, S.R.,Taylor, I.A. (deposition date: 2005-08-23, release date: 2005-10-11, Last modification date: 2023-08-23)

Primary citation

Beuth, B.,Pennell, S.,Arnvig, K.B.,Martin, S.R.,Taylor, I.A.
Structure of a Mycobacterium tuberculosis NusA-RNA complex.
Embo J., 24:3576-3587, 2005

PubMed Abstract: 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.

PubMed: 16193062
DOI: 10.1038/sj.emboj.7600829

Experimental method

X-RAY DIFFRACTION (1.5 Å)