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Wittwer, M.* ; Luo, Q.* ; Kaila, V.R.I.* ; Dames, S.A.

Oxidative unfolding of the rubredoxin domain and the natively disordered N-terminal region regulate the catalytic activity of Mycobacterium tuberculosis protein kinase G.

J. Biol. Chem. 291, 27062-27072 (2016)
Publ. Version/Full Text Postprint Research data DOI PMC
Open Access Green
Mycobacterium tuberculosis escapes killing in human macrophages by secreting protein kinase G (PknG). PknG intercepts host signaling to prevent fusion of the phagosome engulfing the mycobacteria with the lysosome and, thus, their degradation. The N-terminal NORS (no regulatory secondary structure) region of PknG (approximately residues 1-75) has been shown to play a role in PknG regulation by (auto)phosphorylation, whereas the following rubredoxin-like metal-binding motif (RD, residues ∼74-147) has been shown to interact tightly with the subsequent catalytic domain (approximately residues 148-420) to mediate its redox regulation. Deletions or mutations in NORS or the redox-sensitive RD significantly decrease PknG survival function. Based on combined NMR spectroscopy, in vitro kinase assay, and molecular dynamics simulation data, we provide novel insights into the regulatory roles of the N-terminal regions. The NORS region is indeed natively disordered and rather dynamic. Consistent with most earlier data, autophosphorylation occurs in our assays only when the NORS region is present and, thus, in the NORS region. Phosphorylation of it results only in local conformational changes and does not induce interactions with the subsequent RD. Although the reduced, metal-bound RD makes tight interactions with the following catalytic domain in the published crystal structures, it can also fold in its absence. Our data further suggest that oxidation-induced unfolding of the RD regulates substrate access to the catalytic domain and, thereby, PknG function under different redox conditions, e.g. when exposed to increased levels of reactive oxidative species in host macrophages.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords Mycobacterium tuberculosis; NMR; autophosphorylation; intrinsically disordered protein; metal ion-protein interaction; molecular dynamics; oxidative stress; protein kinase G (PKG); protein phosphorylation; redox regulation; Pathogenic Mycobacteria; Molecular-dynamics; Dipolar Couplings; Structural Basis; Stress-response; Amino-acids; Nmr; Survival; Zinc; Pkng
ISSN (print) / ISBN 0021-9258
e-ISSN 1083-351X
Journal Journal of Biological Chemistry, The
Quellenangaben Volume: 291, Issue: 53, Pages: 27062-27072 Article Number: , Supplement: ,
Publisher American Society for Biochemistry and Molecular Biology
Publishing Place Bethesda
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Institute of Structural Biology (STB)