Skip to main content

Research Repository

Advanced Search

The Structure of the Transcriptional Repressor KstR in Complex with CoA Thioester Cholesterol Metabolites Sheds Light on the Regulation of Cholesterol Catabolism in Mycobacterium tuberculosis

Ho, N A T; Dawes, S S; Crowe, A M; Casabon, I; Gao, C; Kendall, S L; Baker, E N; Eltis, L D; Lott, J S

Authors

N A T Ho

S S Dawes

A M Crowe

I Casabon

C Gao

S L Kendall

E N Baker

L D Eltis

J S Lott



Abstract

Cholesterol can be a major carbon source for Mycobacterium tuberculosis during infection, both at an early stage in the macrophage phagosome and later within the necrotic granuloma. KstR is a highly conserved TetR family transcriptional repressor that regulates a large set of genes responsible for cholesterol catabolism. Many genes in this regulon, including kstR, are either induced during infection or are essential for survival of M. tuberculosis in vivo. In this study, we identified two ligands for KstR, both of which are CoA thioester cholesterol metabolites with four intact steroid rings. A metabolite in which one of the rings was cleaved was not a ligand. We confirmed the ligand-protein interactions using intrinsic tryptophan fluorescence and showed that ligand binding strongly inhibited KstR-DNA binding using surface plasmon resonance (IC50 for ligand = 25 nM). Crystal structures of the ligand-free form of KstR show variability in the position of the DNA-binding domain. In contrast, structures of KstR·ligand complexes are highly similar to each other and demonstrate a position of the DNA-binding domain that is unfavorable for DNA binding. Comparison of ligand-bound and ligand-free structures identifies residues involved in ligand specificity and reveals a distinctive mechanism by which the ligand-induced conformational change mediates DNA release.

Citation

Ho, N. A. T., Dawes, S. S., Crowe, A. M., Casabon, I., Gao, C., Kendall, S. L., …Lott, J. S. (2016). The Structure of the Transcriptional Repressor KstR in Complex with CoA Thioester Cholesterol Metabolites Sheds Light on the Regulation of Cholesterol Catabolism in Mycobacterium tuberculosis. Journal of Biological Chemistry, 291(14), 7256-7266. https://doi.org/10.1074/jbc.M115.707760

Journal Article Type Article
Acceptance Date Feb 8, 2016
Publication Date Apr 1, 2016
Deposit Date Sep 30, 2016
Publicly Available Date Sep 30, 2016
Journal JOURNAL OF BIOLOGICAL CHEMISTRY
Print ISSN 0021-9258
Publisher American Society for Biochemistry and Molecular Biology
Peer Reviewed Peer Reviewed
Volume 291
Issue 14
Pages 7256-7266
DOI https://doi.org/10.1074/jbc.M115.707760
Public URL https://rvc-repository.worktribe.com/output/1397113

Files








You might also like



Downloadable Citations