Coordination and redox state-dependent structural changes of the heme-based oxygen sensor AfGcHK associated with intraprotein signal transduction

Kód výsledku v IS VaVaI

RIV/61388971:_____/17:00483974 - isvavai.cz

Nalezeny alternativní kódy

RIV/86652036:_____/17:00483974 RIV/68407700:21340/17:00316855 RIV/00216208:11310/17:10367486

Výsledek na webu

http://dx.doi.org/10.1074/jbc.M117.817023

DOI - Digital Object Identifier

10.1074/jbc.M117.817023

Jazyk výsledku

angličtina

Název v původním jazyce

Coordination and redox state-dependent structural changes of the heme-based oxygen sensor AfGcHK associated with intraprotein signal transduction

Popis výsledku v původním jazyce

The heme-based oxygen sensor histidine kinase AfGcHK is part of a two-component signal transduction system in bacteria. O-2 binding to the Fe(II) heme complex of its N-terminal globin domain strongly stimulates autophosphorylation at His(183) in its C-terminal kinase domain. The 6-coordinate heme Fe(III)-OH- and -CN- complexes of AfGcHK are also active, but the 5-coordinate heme Fe(II) complex and the heme-free apo-form are inactive. Here, we determined the crystal structures of the isolated dimeric globin domains of the active Fe(III)-CN- and inactive 5-coordinate Fe(II) forms, revealing striking structural differences on the heme-proximal side of the globin domain. Using hydrogen/deuterium exchange coupled with mass spectrometry to characterize the conformations of the active and inactive forms of full-length AfGcHK in solution, we investigated the intramolecular signal transduction mechanisms. Major differences between the active and inactive forms were observed on the heme-proximal side (helix H5), at the dimerization interface (helices H6 and H7 and loop L7) of the globin domain and in the ATP-binding site (helices H9 and H11) of the kinase domain. Moreover, separation of the sensor and kinase domains, which deactivates catalysis, increased the solvent exposure of the globin domain-dimerization interface (helix H6) as well as the flex ibility and solvent exposure of helix H11. Together, these results suggest that structural changes at the heme-proximal side, the globin domain-dimerization interface, and the ATP-binding site are important in the signal transduction mechanism of AfGcHK. We conclude that AfGcHK functions as an ensemble of molecules sampling at least two conformational states.

Název v anglickém jazyce

Coordination and redox state-dependent structural changes of the heme-based oxygen sensor AfGcHK associated with intraprotein signal transduction

Popis výsledku anglicky

The heme-based oxygen sensor histidine kinase AfGcHK is part of a two-component signal transduction system in bacteria. O-2 binding to the Fe(II) heme complex of its N-terminal globin domain strongly stimulates autophosphorylation at His(183) in its C-terminal kinase domain. The 6-coordinate heme Fe(III)-OH- and -CN- complexes of AfGcHK are also active, but the 5-coordinate heme Fe(II) complex and the heme-free apo-form are inactive. Here, we determined the crystal structures of the isolated dimeric globin domains of the active Fe(III)-CN- and inactive 5-coordinate Fe(II) forms, revealing striking structural differences on the heme-proximal side of the globin domain. Using hydrogen/deuterium exchange coupled with mass spectrometry to characterize the conformations of the active and inactive forms of full-length AfGcHK in solution, we investigated the intramolecular signal transduction mechanisms. Major differences between the active and inactive forms were observed on the heme-proximal side (helix H5), at the dimerization interface (helices H6 and H7 and loop L7) of the globin domain and in the ATP-binding site (helices H9 and H11) of the kinase domain. Moreover, separation of the sensor and kinase domains, which deactivates catalysis, increased the solvent exposure of the globin domain-dimerization interface (helix H6) as well as the flex ibility and solvent exposure of helix H11. Together, these results suggest that structural changes at the heme-proximal side, the globin domain-dimerization interface, and the ATP-binding site are important in the signal transduction mechanism of AfGcHK. We conclude that AfGcHK functions as an ensemble of molecules sampling at least two conformational states.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10608 - Biochemistry and molecular biology

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Biological Chemistry

ISSN

0021-9258

e-ISSN

—

Svazek periodika

292

Číslo periodika v rámci svazku

51

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

15

Strana od-do

20921-20935

Kód UT WoS článku

000418453400010

EID výsledku v databázi Scopus

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