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Defining Hsp33's Redox-regulated Chaperone Activity and Mapping Conformational Changes on Hsp33 Using Hydrogen-deuterium Exchange Mass Spectrometry
Published on: June 7, 2018
Iron-mediated oxidation induces conformational changes within the redox-sensing protein HbpS
Darío Ortiz de Orué Lucana1, Mareike Roscher, Alf Honigmann
1Department of Applied Genetics of Microorganisms, Faculty of Biology/Chemistry, University of Osnabrück, 49069 Osnabrück, Germany. ortiz@biologie.uni-osnabrueck.de
The Journal of Biological Chemistry
|June 24, 2010
Summary
Heme-binding protein S (HbpS) binds and degrades heme under oxidative stress, releasing iron. This triggers structural changes and modifications in HbpS, controlling the HbpS-SenS-SenR redox stress signaling pathway.
Area of Science:
- Biochemistry
- Molecular Biology
- Protein Chemistry
Background:
- Heme-binding protein S (HbpS) is an extracellular protein involved in sensing redox stress.
- HbpS functions with the two-component system SenS-SenR.
- HbpS interacts with heme and iron ions, modulating SenS phosphorylation.
Purpose of the Study:
- To investigate the structural and conformational changes in HbpS induced by iron-mediated oxidative stress.
- To elucidate the mechanism by which HbpS controls the SenS-SenR signaling cascade.
Main Methods:
- Biochemical and biophysical approaches
- Analysis of HbpS wild type and mutants
- Crystal structure examination
- Mutational analyses
Main Results:
- Iron-mediated oxidative stress induces secondary structure and conformational changes in HbpS.
- HbpS undergoes oxidative modification, forming reactive carbonyl groups and dityrosine bonds.
- A specific tyrosine residue involved in inter-monomer dityrosine formation within the octameric assembly was identified.
Conclusions:
- Oxidative modifications and resulting structural changes in HbpS are crucial for regulating the HbpS-SenS-SenR signaling pathway.
- HbpS acts as a redox stress sensor, integrating heme/iron availability and oxidative conditions to control downstream signaling.
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