Heme protonation affects iron-NO binding in the NO transport protein nitrophorin.

Autor: Auerbach H; Department of Physics, RPTU Kaiserslautern-Landau, 67663 Kaiserslautern, Germany., Faus I; Department of Physics, RPTU Kaiserslautern-Landau, 67663 Kaiserslautern, Germany., Rackwitz S; Department of Physics, RPTU Kaiserslautern-Landau, 67663 Kaiserslautern, Germany., Wolny JA; Department of Physics, RPTU Kaiserslautern-Landau, 67663 Kaiserslautern, Germany., Chumakov AI; ESRF-The European Synchrotron, CS40220 38043, Grenoble Cedex 9, France., Knipp M; Max Planck Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim an der Ruhr, Germany; Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstraße 150, 44780 Bochum, Germany., Walker FA; Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ 85721-0041, United States., Schünemann V; Department of Physics, RPTU Kaiserslautern-Landau, 67663 Kaiserslautern, Germany. Electronic address: schuene@physik.uni-kl.de.
Jazyk: angličtina
Zdroj: Journal of inorganic biochemistry [J Inorg Biochem] 2023 Sep; Vol. 246, pp. 112281. Date of Electronic Publication: 2023 Jun 10.
DOI: 10.1016/j.jinorgbio.2023.112281
Abstrakt: The nitrophorins (NPs) comprise an unusual group of heme proteins with stable ferric heme iron nitric oxide (Fe-NO) complexes. They are found in the salivary glands of the blood-sucking kissing bug Rhodnius prolixus, which uses the NPs to transport the highly reactive signaling molecule NO. Nuclear resonance vibrational spectroscopy (NRVS) of both isoform NP2 and a mutant NP2(Leu132Val) show, after addition of NO, a strong structured vibrational band at around 600 cm -1 , which is due to modes with significant Fe-NO bending and stretching contribution. Based on a hybrid calculation method, which uses density functional theory and molecular mechanics, it is demonstrated that protonation of the heme carboxyl groups does influence both the vibrational properties of the Fe-NO entity and its electronic ground state. Moreover, heme protonation causes a significant increase of the gap between the highest occupied and lowest unoccupied molecular orbital by almost one order of magnitude leading to a stabilization of the Fe-NO bond.
Competing Interests: Declaration of Competing Interest The authors have no competing interests to declare.
(Copyright © 2023. Published by Elsevier Inc.)
Databáze: MEDLINE
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