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Differential local stability governs the metamorphic fold-switch of bacterial virulence factor RfaH

Title data

Galaz-Davison, Pablo ; Molina, José Alejandro ; Silletti, Steve ; Komives, Elizabeth A. ; Knauer, Stefan H. ; Artsimovitch, Irina ; Ramírez-Sarmiento, César A.:
Differential local stability governs the metamorphic fold-switch of bacterial virulence factor RfaH.
In: Biophysical Journal. (2019) .
ISSN 1542-0086
DOI: https://doi.org/10.1016/j.bpj.2019.11.014

Abstract in another language

A regulatory factor RfaH, present in many Gram-negative bacterial pathogens, is required for transcription and translation of long operons encoding virulence determinants. Escherichia coli RfaH action is controlled by a unique large-scale structural rearrangement triggered by recruitment to transcription elongation complexes through a specific DNA sequence within these operons. Upon recruitment, the C-terminal domain of this two-domain protein refolds from an α-hairpin, which is bound to the RNA polymerase binding site within the N-terminal domain of RfaH, into an unbound β-barrel that interacts with the ribosome to enable translation. Although structures of the autoinhibited (α-hairpin) and active (β-barrel) states and plausible refolding pathways have been reported, how this reversible switch is encoded within RfaH sequence and structure is poorly understood. Here, we combined hydrogen-deuterium exchange measurements by mass spectrometry and nuclear magnetic resonance with molecular dynamics to evaluate the differential local stability between both RfaH folds. Deuteron incorporation reveals that the tip of the C-terminal hairpin (residues 125-145) is stably folded in the autoinhibited state (∼20% deuteron incorporation), while the rest of this domain is highly flexible (>40% deuteron incorporation) and its flexibility only decreases in the β-folded state. Computationally-predicted ΔGs agree with these results by displaying similar anisotropic stability within the tip of the α-hairpin and on neighboring N-terminal domain residues. Remarkably, the β-folded state shows comparable stability to non-metamorphic homologs. Our findings provide information critical for understanding the metamorphic behavior of RfaH and other chameleon proteins, and for devising targeted strategies to combat bacterial diseases.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Biopolymers > Lehrstuhl Biopolymere - Apl. Prof. Dr. Birgitta Wöhrl
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 540 Chemistry
500 Science > 570 Life sciences, biology
Date Deposited: 22 Nov 2019 07:32
Last Modified: 22 Nov 2019 07:32
URI: https://eref.uni-bayreuth.de/id/eprint/53371