Ca 2+ binding shifts dimeric dual oxidase's truncated EF-hand domain to monomer.

Autor: Wei CC; Department of Chemistry, College of Arts and Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, USA; Department of Pharmaceutical Sciences, College of Pharmacy, Southern Illinois University Edwardsville, Edwardsville, IL 62026, USA. Electronic address: cwei@siue.edu., Razzak AA; Department of Chemistry, College of Arts and Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, USA., Ghasemi H; Department of Chemistry, College of Arts and Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, USA., Khedri R; Department of Chemistry, College of Arts and Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, USA., Fraase A; Department of Chemistry, College of Arts and Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, USA.
Jazyk: angličtina
Zdroj: Biophysical chemistry [Biophys Chem] 2024 Sep; Vol. 312, pp. 107271. Date of Electronic Publication: 2024 May 24.
DOI: 10.1016/j.bpc.2024.107271
Abstrakt: Hydrogen peroxide, produced by Dual Oxidase (Duox), is essential for thyroid hormone synthesis. Duox activation involves Ca 2+ binding to its EF-hand Domain (EFD), which contains two EF-hands (EFs). In this study, we characterized a truncated EFD using spectrometry, calorimetry, electrophoretic mobility, and gel filtration to obtain its Ca 2+ binding thermodynamic and kinetics, as well as to assess the associated conformational changes. Our results revealed that its 2nd EF-hand (EF2) exhibits a strong exothermic Ca 2+ binding (K a  = 10 7  M -1 ) while EF1 shows a weaker binding (K a  = 10 5  M -1 ), resulting in the burial of its negatively charged residues. The Ca 2+ binding to EFD results in a stable structure with a melting temperature shifting from 67 to 99 °C and induces a structural transition from a dimeric to monomeric form. EF2 appears to play a role in dimer formation in its apo form, while the hydrophobic exposure of Ca 2+ -bound-EF1 is crucial for dimer formation in its holo form. The result is consistent with structures obtained from Cryo-EM, indicating that a stable structure of EFD with hydrophobic patches upon Ca 2+ binding is vital for its Duox's domain-domain interaction for electron transfer.
Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Chin-Chuan Wei reports financial support was provided by National Science Foundation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023. Published by Elsevier B.V.)
Databáze: MEDLINE
Externí odkaz: