INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
Access and Binding of H2S to Hemeproteins: The Case of HbI of Lucina pectinata
Autor/es:
BOUBETA, FERNANDO M.; BOECHI, LEONARDO; ESTRIN, DARIO A.; ESTRIN, DARIO A.; BARI, SARA E.; BARI, SARA E.; BOUBETA, FERNANDO M.; BOECHI, LEONARDO
Revista:
JOURNAL OF PHYSICAL CHEMISTRY B - (Print)
Editorial:
AMER CHEMICAL SOC
Referencias:
Año: 2016 vol. 120 p. 9642 - 9642
ISSN:
1520-6106
Resumen:
Hydrogen sulfide (H2S) was recently discovered as a gasotransmitter, capable of coordinating to the heme iron of hemeproteins. H2S is unique for its ability to render varying concentrations of the nucleophilic conjugate bases (HS- or S2-), either as free or bound species with expected outcomes on its further reactivity. There is no direct evidence about which species (H2S, HS-, or S2-) coordinates to the iron. We performed computer simulations to address the migration and binding processes of H2S species to the hemoglobin I of Lucina pectinata, which exhibits the highest affinity for the substrate measured to date. We found that H2S is the most favorable species in the migration from the bulk to the active site, through an internal pathway of the protein. After the coordination of H2S, an array of clustered water molecules modifies the active site environment, and assists in the subsequent deprotonation of the ligand, forming Fe(III)-SH-. The feasibility of the second deprotonation of the coordinated ligand is also discussed.