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Disruption of the dimerization interface of the sensing domain in the dimeric heme-based oxygen sensor Af GcHK abolishes bacterial signal transduction
Authors:
Tereza
Skalova
(Institute of Biotechnology of the Czech Academy of Sciences)
,
Alzbeta
Lengalova
(Charles University)
,
Jan
Dohnalek
(Institute of Biotechnology of the Czech Academy of Sciences)
,
Karl
Harlos
(University of Oxford)
,
Peter
Mihalcin
(Charles University)
,
Petr
Kolenko
(Czech Technical University in Prague)
,
Martin
Stranava
(Charles University)
,
Jan
Blaha
(Charles University)
,
Toru
Shimizu
(Charles University)
,
Markéta
Martínková
(Charles University)
Co-authored by industrial partner:
No
Type:
Journal Paper
Journal:
Journal Of Biological Chemistry
State:
Published (Approved)
Published:
December 2019
Diamond Proposal Number(s):
10627

Abstract: The heme-based oxygen sensor protein AfGcHK is a globin-coupled histidine kinase in the soil bacterium Anaeromyxobacter sp. Fw109-5. Its C-terminal functional domain exhibits autophosphorylation activity induced by oxygen binding to the heme Fe(II) complex located in the oxygen-sensing N-terminal globin domain. A detailed understanding of the signal transduction mechanisms in heme-containing sensor proteins remains elusive. Here, we investigated the role of the globin domain’s dimerization interface in signal transduction in AfGcHK. We present a crystal structure of a monomeric imidazole-bound AfGcHK globin domain at 1.8 Å resolution, revealing that the helices of the wild-type globin dimer are under tension and suggesting that Tyr-15 plays a role in both this tension and the globin domain’s dimerization. Biophysical experiments revealed that whereas the isolated wild-type globin domain is dimeric in solution, the Y15A and Y15G variants in which Tyr-15 is replaced with Ala or Gly, respectively, are monomeric. Additionally, we found that although the dimerization of the full-length protein is preserved via the kinase domain dimerization interface in all variants, full-length AfGcHK variants bearing the Y15A or Y15G substitutions lack enzymatic activity. The combined structural and biophysical results presented here indicate that Tyr-15 plays a key role in the dimerization of the globin domain of AfGcHK and that globin domain dimerization is essential for internal signal transduction and autophosphorylation in this protein. These findings provide critical insights into the signal transduction mechanism of the histidine kinase AfGcHK from Anaeromyxobacter.
Journal Keywords: dimerization interface; globin; heme-based oxygen sensor; two component system; signal transduction; cell signaling; heme; bacterial protein kinase; histidine kinase; crystal structure
Diamond Keywords: Bacteria
Subject Areas:
Biology and Bio-materials
Instruments:
I02-Macromolecular Crystallography
Added On:
08/01/2020 10:55
Documents:
jbc.RA119.011574.full.pdf
Discipline Tags:
Structural biology
Biophysics
Life Sciences & Biotech
Technical Tags:
Diffraction
Macromolecular Crystallography (MX)