4KMC

Structure analysis of M. Tuberculosis rRNA transcriptional regulator CarD and its interaction with T. Aquaticus RNA polymerase-BETA1 domain

Summary for 4KMC

• Entry DOI: 10.2210/pdb4kmc/pdb
• Descriptor: RNA polymerase-binding transcription factor CarD (2 entities in total)
• Functional Keywords: unknown fold, rrna transcriptional regulator, rna polymerase beta1 domain, transcription
• Biological source: Mycobacterium tuberculosis
• Total number of polymer chains: 1
• Total formula weight: 8883.03

Authors

Gangwar, S.P.,Meena, S.R.,Saxena, A.K. (deposition date: 2013-05-08, release date: 2014-02-19, Last modification date: 2024-03-20)

Primary citation

Gangwar, S.P.,Meena, S.R.,Saxena, A.K.
Structure of the carboxy-terminal domain of Mycobacterium tuberculosis CarD protein: an essential rRNA transcriptional regulator.
Acta Crystallogr.,Sect.F, 70:160-165, 2014

PubMed Abstract: The CarD protein is highly expressed in mycobacterial strains under basal conditions and is transcriptionally induced during multiple types of genotoxic stress and starvation. The CarD protein binds the β subunit of RNA polymerase and influences gene expression. The disruption of interactions between CarD and the β subunit of RNA polymerase has a significant effect on mycobacterial survival, resistance to stress and pathogenesis. To understand the structure of CarD and its interaction with the β subunit of RNA polymerase, Mycobacterium tuberculosis CarD (MtbCarD) and the Thermus aquaticus RNA polymerase β subunit were recombinantly expressed and purified. Secondary-structure analysis using circular-dichroism spectroscopy indicated that MtbCarD contains ∼ 60% α-helix, ∼ 7% β-sheet and ∼ 33% random-coil structure. The C-terminal domain of MtbCarD (CarD(83-161)) was crystallized and its X-ray structure was determined at 2.1 Å resolution. CarD(83-161) forms a distorted Y-shaped structure containing bundles of three helices connected by a loop. The residues forming the distorted Y-shaped structure are highly conserved in CarD sequences from other mycobacterial species. Comparison of the CarD(83-161) structure with the recently determined full-length M. tuberculosis and T. thermophilus CarD crystal structures revealed structural differences in residues 141-161 of the C-terminal domain of the CarD(83-161) structure. The structural changes in the CarD(83-161) structure occurred owing to proteolysis and crystallization artifacts.

PubMed: 24637748
DOI: 10.1107/S2053230X13034407

Experimental method

X-RAY DIFFRACTION (2.15 Å)