Mycobacterium tuberculosis cAMP Receptor Protein (Rv3676) Differs from the Escherichia coli Paradigm in Its cAMP Binding and DNA Binding Properties and Transcription Activation Properties
By Melanie R. Stapleton, I. Haq, D. Hunt, Kristine B. Arnvig, P. Artymiuk, R. Buxton, Jeffrey Green. 2009
85 citations recorded by the source corpus.
The pathogen Mycobacterium tuberculosis produces a burst of cAMP upon infection of macrophages. Bacterial cyclic AMP receptor proteins (CRP) are transcription factors that respond to cAMP by binding at target promoters when cAMP concentrations increase. Rv3676 (CRPMt) is a CRP family protein that regulates expression of genes (rpfA and whiB1) that are potentially involved in M. tuberculosis persistence and/or emergence from the dormant state. Here, the CRPMt homodimer is shown to bind two molecules of cAMP (one per protomer) at noninteracting sites. Furthermore, cAMP binding by CRPMt was relatively weak, entropy driven, and resulted in a relatively small enhancement in DNA binding. Tandem CRPMt-binding sites (CRP1 at −58.5 and CRP2 at −37.5) were identified at the whiB1 promoter (PwhiB1). In vitro transcription reactions showed that CRP1 is an activating site and that CRP2, which was only occupied in the presence of cAMP or at high CRPMt concentrations in the absence of cAMP, is a repressing site. Binding of CRPMt to CRP1 was not essential for open complex formation but was required for transcription activation. Thus, these data suggest that binding of CRPMt to the PwhiB1 CRP1 site activates transcription at a step after open complex formation. In contrast, high cAMP concentrations allowed occupation of both CRP1 and CRP2 sites, resulting in inhibition of open complex formation. Thus, M. tuberculosis CRP has evolved several distinct characteristics, compared with the Escherichia coli CRP paradigm, to allow it to regulate gene expression against a background of high concentrations of cAMP.
Subfields: Genetics, Infectious Diseases, Molecular Medicine
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Genetics
Citations in the corpus
- The Transcriptional Regulators of the CRP Family Regulate Different Essential Bacterial Functions and Can Be Inherited Vertically and Horizontally (2017, background): “The CRP-orthologs from different bacterial species have different cAMP binding-affinities, which correlate with subtle changes in their structure (Stapleton et al., 2010; Serate et al., 2011; Arce-Rodríguez et al., 2012).”
- Directed Evolution of the Escherichia coli cAMP Receptor Protein at the cAMP Pocket* (2015, background): “OCTOBER 30, 2015•VOLUME 290•NUMBER 44 JOURNAL OF BIOLOGICAL CHEMISTRY 26591 Thr/Ser, Thr/Thr, and Thr/Asn Are Predominant Residue Pairs at the Positions Analogous to CRP Thr127 and Ser128 in cAMP-sensing CRP Homologs—”
- Genomic mapping of cAMP receptor protein (CRPMt) in Mycobacterium tuberculosis: relation to transcriptional start sites and the role of CRPMt as a transcription factor (2014, methodology): “Alignment of ChIP-seq and TSS data sets also reproduced the more complex situation of tandem activating and inhibitory binding sites in the whiB1 promoter (21).”
- The Crystal Structures of Apo and cAMP-Bound GlxR from Corynebacterium glutamicum Reveal Structural and Dynamic Changes upon cAMP Binding in CRP/FNR Family Transcription Factors (2014, result): “This notion is supported by results from Mt-CRP, which shares the asparagine at this position and previous work on Ec-CRP where the Ser128 to Ala mutation abolished allosteric behavior [48, 49].”
- Cyclic AMP Signaling in Mycobacteria (2014, background): “tuberculosis whiB1, a member of the Wbl (WhiB-like) family, is both positively and negatively regulated by CRPMt (55, 61, 74), depending on cAMP levels and which of the multiple binding sites are bound.”