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New Insights Regarding Hemin Inhibition of the Purified Rat Brain 2-Oxoglutarate Carrier and Relationships with Mitochondrial Dysfunction

A kinetic analysis of the transport assays on the purified rat brain 2-oxoglutarate/malate carrier (OGC) was performed starting from our recent results reporting about a competitive inhibitory behavior of hemin, a physiological porphyrin derivative, on the OGC reconstituted in an active form into pr...

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Autores principales: Miniero, Daniela Valeria, Gambacorta, Nicola, Spagnoletta, Anna, Tragni, Vincenzo, Loizzo, Stefano, Nicolotti, Orazio, Pierri, Ciro Leonardo, De Palma, Annalisa
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9785169/
https://www.ncbi.nlm.nih.gov/pubmed/36556135
http://dx.doi.org/10.3390/jcm11247519
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author Miniero, Daniela Valeria
Gambacorta, Nicola
Spagnoletta, Anna
Tragni, Vincenzo
Loizzo, Stefano
Nicolotti, Orazio
Pierri, Ciro Leonardo
De Palma, Annalisa
author_facet Miniero, Daniela Valeria
Gambacorta, Nicola
Spagnoletta, Anna
Tragni, Vincenzo
Loizzo, Stefano
Nicolotti, Orazio
Pierri, Ciro Leonardo
De Palma, Annalisa
author_sort Miniero, Daniela Valeria
collection PubMed
description A kinetic analysis of the transport assays on the purified rat brain 2-oxoglutarate/malate carrier (OGC) was performed starting from our recent results reporting about a competitive inhibitory behavior of hemin, a physiological porphyrin derivative, on the OGC reconstituted in an active form into proteoliposomes. The newly provided transport data and the elaboration of the kinetic equations show evidence that hemin exerts a mechanism of partially competitive inhibition, coupled with the formation of a ternary complex hemin-carrier substrate, when hemin targets the OGC from the matrix face. A possible interpretation of the provided kinetic analysis, which is supported by computational studies, could indicate the existence of a binding region responsible for the inhibition of the OGC and supposedly involved in the regulation of OGC activity. The proposed regulatory binding site is located on OGC mitochondrial matrix loops, where hemin could establish specific interactions with residues involved in the substrate recognition and/or conformational changes responsible for the translocation of mitochondrial carrier substrates. The regulatory binding site would be placed about 6 Å below the substrate binding site of the OGC, facing the mitochondrial matrix, and would allow the simultaneous binding of hemin and 2-oxoglutarate or malate to different regions of the carrier. Overall, the presented experimental and computational analyses help to shed light on the possible existence of the hemin-carrier substrate ternary complex, confirming the ability of the OGC to bind porphyrin derivatives, and in particular hemin, with possible consequences for the mitochondrial redox state mediated by the malate/aspartate shuttle led by the mitochondrial carriers OGC and AGC.
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spelling pubmed-97851692022-12-24 New Insights Regarding Hemin Inhibition of the Purified Rat Brain 2-Oxoglutarate Carrier and Relationships with Mitochondrial Dysfunction Miniero, Daniela Valeria Gambacorta, Nicola Spagnoletta, Anna Tragni, Vincenzo Loizzo, Stefano Nicolotti, Orazio Pierri, Ciro Leonardo De Palma, Annalisa J Clin Med Article A kinetic analysis of the transport assays on the purified rat brain 2-oxoglutarate/malate carrier (OGC) was performed starting from our recent results reporting about a competitive inhibitory behavior of hemin, a physiological porphyrin derivative, on the OGC reconstituted in an active form into proteoliposomes. The newly provided transport data and the elaboration of the kinetic equations show evidence that hemin exerts a mechanism of partially competitive inhibition, coupled with the formation of a ternary complex hemin-carrier substrate, when hemin targets the OGC from the matrix face. A possible interpretation of the provided kinetic analysis, which is supported by computational studies, could indicate the existence of a binding region responsible for the inhibition of the OGC and supposedly involved in the regulation of OGC activity. The proposed regulatory binding site is located on OGC mitochondrial matrix loops, where hemin could establish specific interactions with residues involved in the substrate recognition and/or conformational changes responsible for the translocation of mitochondrial carrier substrates. The regulatory binding site would be placed about 6 Å below the substrate binding site of the OGC, facing the mitochondrial matrix, and would allow the simultaneous binding of hemin and 2-oxoglutarate or malate to different regions of the carrier. Overall, the presented experimental and computational analyses help to shed light on the possible existence of the hemin-carrier substrate ternary complex, confirming the ability of the OGC to bind porphyrin derivatives, and in particular hemin, with possible consequences for the mitochondrial redox state mediated by the malate/aspartate shuttle led by the mitochondrial carriers OGC and AGC. MDPI 2022-12-19 /pmc/articles/PMC9785169/ /pubmed/36556135 http://dx.doi.org/10.3390/jcm11247519 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Miniero, Daniela Valeria
Gambacorta, Nicola
Spagnoletta, Anna
Tragni, Vincenzo
Loizzo, Stefano
Nicolotti, Orazio
Pierri, Ciro Leonardo
De Palma, Annalisa
New Insights Regarding Hemin Inhibition of the Purified Rat Brain 2-Oxoglutarate Carrier and Relationships with Mitochondrial Dysfunction
title New Insights Regarding Hemin Inhibition of the Purified Rat Brain 2-Oxoglutarate Carrier and Relationships with Mitochondrial Dysfunction
title_full New Insights Regarding Hemin Inhibition of the Purified Rat Brain 2-Oxoglutarate Carrier and Relationships with Mitochondrial Dysfunction
title_fullStr New Insights Regarding Hemin Inhibition of the Purified Rat Brain 2-Oxoglutarate Carrier and Relationships with Mitochondrial Dysfunction
title_full_unstemmed New Insights Regarding Hemin Inhibition of the Purified Rat Brain 2-Oxoglutarate Carrier and Relationships with Mitochondrial Dysfunction
title_short New Insights Regarding Hemin Inhibition of the Purified Rat Brain 2-Oxoglutarate Carrier and Relationships with Mitochondrial Dysfunction
title_sort new insights regarding hemin inhibition of the purified rat brain 2-oxoglutarate carrier and relationships with mitochondrial dysfunction
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9785169/
https://www.ncbi.nlm.nih.gov/pubmed/36556135
http://dx.doi.org/10.3390/jcm11247519
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