Česká společnost pro hmotnostní spektrometrii

(3. konference České společnosti pro hmotnostní spektrometrii - WeP-026)
WrbA, an E. coli stress-response protein probed by ion mobility mass spectrometry

Alan Kádek ^1,2 *, Julien Marcoux ³, Iryna Kishko ^4,5, Zdeněk Kukačka ^1,2, Petr Man ^1,2, Carol V. Robinson ³, Petr Novák ^1,2, Rüdiger Ettrich ^4,5, Jannette Carey ⁶

1. Institute of Microbiology, ASCR, Prague, CZECH REPUBLIC
2. Department of Biochemistry, Faculty of Science, Charles University in Prague, CZECH REPUBLIC
3. Department of Chemistry, University of Oxford, UNITED KINGDOM
4. Institute of Nanobiology and Structural Biology, ASCR, Nove Hrady, CZECH REPUBLIC
5. Faculty of Sciences, University of South Bohemia, Nove Hrady, CZECH REPUBLIC
6. Chemistry Department, Princeton University, Princeton, New Jersey, UNITED STATES OF AMERICA

Abstrakt

Tryptophan repressor-binding protein A (WrbA), more correctly called FMN-dependent NAD(P)H:quinone oxidoreductase, is an E. coli protein interesting for its involvement in bacterial responses to oxidative stress. Its biologically functional assembly is an obligate homotetramer held together by non-covalent interactions. Although a 1.2 Å high-resolution structure of this tetramer has been solved by X-ray crystallography, the dynamics of the protein in solution still remain under investigation. Of particular interest is the process of tetramer formation, during which WrbA is supposed to form a monomer-dimer-tetramer dynamic equilibrium.

In the present study, we utilized native electrospray ionization coupled with ion mobility mass spectrometry to gently transfer the intact non-covalent WrbA complexes into the gas phase while preserving their structure and to analyze the oligomeric states and conformations of this protein under different solution conditions. The results have shown a high stabilizing effect of FMN cofactor on the tetrameric structure of WrbA complex as well as provided an insight into the mechanism of the tetramer formation.

* Korespondující autor: kadek@biomed.cas.cz

Poděkování:

This work was funded by Instruct, part of the European Strategy Forum on Research Infrastructures (ESFRI) and supported by national member subscriptions; Institutional Research Concept of the Institute of Microbiology RVO 61388971; European Regional Development Funds (CZ.1.07/2.3.00/20.0055, CZ.1.07/2.3.00/30.0003 and CZ.1.05/1.1.00/02.0109); Research Project of Charles University (UNCE 204025/2012) and by the Grant Agency of Charles University (800413).