Interactions of human mitochondrial Ferredoxin 1 (Adrenodoxin) by NMR; modulation by cytochrome P450 substrate and by truncation of the C-terminal tail.

Autor: Jay N; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA. Electronic address: njay@buffalo.edu., McGlohon JE; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA. Electronic address: janiemcg@buffalo.edu., Estrada DF; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA. Electronic address: dfestrad@buffalo.edu.
Jazyk: angličtina
Zdroj: Journal of inorganic biochemistry [J Inorg Biochem] 2023 Dec; Vol. 249, pp. 112370. Date of Electronic Publication: 2023 Sep 12.
DOI: 10.1016/j.jinorgbio.2023.112370
Abstrakt: Human Ferredoxin 1, also referred to as Adrenodoxin (Adx), is the sole electron carrier supporting the function of all seven mitochondrial cytochrome P450 (CYP) enzymes. Adx utilizes conserved negatively charged residues along its α-helix3 to interact with either the proximal surface of CYP enzymes or the binding surface of Adrendodoxin Reductase (AdR). However, in the oxidized state, Adx assumes a monomer-homodimer equilibrium that requires the presence of its unstructured C-terminal tail. Crystallographic structures of full-length human Adx dimers indicate that part of the binding surface necessary for its interactions with CYPs or with AdR is partially occluded by the dimer interface. In this study, protein NMR spectroscopy was used to interrogate the interactions between full-length (2-124) or truncated monomeric (2-108) human Adx and human CYP24A1 (with and without its vitamin-D substrate) as well as interactions with AdR. Here, monomeric Adx induced a similar pattern of peak broadening as that induced by addition of CYP24A1 substrate, consistent with a 1:1 Adx:CYP interaction as the functional complex. Additionally, removal of the C-terminal tail appears to enhance the interaction with AdR, despite removal of some of the AdR contacts in the tail region. This finding was also supported by an NMR competition assay. These findings suggest that the Adx dimers do not undergo meaningful interactions with either CYP or AdR, but may instead be responsible for regulating access to monomeric Adx. These conclusions are discussed in the context of a revised model of the Adx electron shuttle mechanism.
Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: D. Fernando Estrada reports financial support was provided by National Institute of General Medical Sciences.
(Copyright © 2023 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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