Modulating the nitrite reductase activity of globins by varying the heme substituents: Utilizing myoglobin as a model system

Mary Grace I. Galinato, Robert S. Fogle, Amanda Stetz, Jhenny F. Galan

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Globins, such as hemoglobin (Hb) and myoglobin (Mb), have gained attention for their ability to reduce nitrite (NO2-) to nitric oxide (NO). The molecular interactions that regulate this chemistry are not fully elucidated, therefore we address this issue by investigating one part of the active site that may control this reaction. Here, the effects of the 2,4-heme substituents on the nitrite reductase (NiR) reaction, and on the structures and energies of the ferrous nitrite intermediates, are investigated using Mb as a model system. This is accomplished by studying Mbs with hemes that have different 2,4-R groups, namely diacetyldeuteroMb (-acetyl), protoMb (wild-type (wt) Mb, -vinyl), deuteroMb (-H), and mesoMb (-ethyl). While trends on the natural charge on Fe and O-atom of bound nitrite are observed among the series of Mbs, the FeII-NPyr (Pyr = pyrrole) and FeII-NHis93 (His = histidine) bond lengths do not significantly change. Kinetic analysis shows increasing NiR activity as follows: diacetyldeuteroMb < wt Mb < deuteroMb < mesoMb. Nitrite binding energy calculations of the different MbII-nitrite conformations demonstrate the N-bound complexes to be more stable than the O-bound complexes for all the different types of heme structures, with diacetyldeuteroMb having the greatest nitrite binding affinity. Spectral deconvolution on the final product generated from the reaction between MbII and NO2- for the reconstituted Mbs indicates the formation of 1:1 MbIII and MbII-NO. The electronic changes induced by the -R groups on the 2,4-positions do not alter the stoichiometric ratio of the products, resembling wt Mb.

Original languageEnglish (US)
Pages (from-to)7-20
Number of pages14
JournalJournal of Inorganic Biochemistry
Volume154
DOIs
StatePublished - Jan 1 2016

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Nitrite Reductases
Globins
Myoglobin
Nitrites
Heme
Nitric Oxide
Pyrroles
Molecular interactions
Bond length
Deconvolution
Binding energy
Histidine
Conformations
Catalytic Domain
Hemoglobins
Atoms
Kinetics

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Inorganic Chemistry

Cite this

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title = "Modulating the nitrite reductase activity of globins by varying the heme substituents: Utilizing myoglobin as a model system",
abstract = "Globins, such as hemoglobin (Hb) and myoglobin (Mb), have gained attention for their ability to reduce nitrite (NO2-) to nitric oxide (NO). The molecular interactions that regulate this chemistry are not fully elucidated, therefore we address this issue by investigating one part of the active site that may control this reaction. Here, the effects of the 2,4-heme substituents on the nitrite reductase (NiR) reaction, and on the structures and energies of the ferrous nitrite intermediates, are investigated using Mb as a model system. This is accomplished by studying Mbs with hemes that have different 2,4-R groups, namely diacetyldeuteroMb (-acetyl), protoMb (wild-type (wt) Mb, -vinyl), deuteroMb (-H), and mesoMb (-ethyl). While trends on the natural charge on Fe and O-atom of bound nitrite are observed among the series of Mbs, the FeII-NPyr (Pyr = pyrrole) and FeII-NHis93 (His = histidine) bond lengths do not significantly change. Kinetic analysis shows increasing NiR activity as follows: diacetyldeuteroMb < wt Mb < deuteroMb < mesoMb. Nitrite binding energy calculations of the different MbII-nitrite conformations demonstrate the N-bound complexes to be more stable than the O-bound complexes for all the different types of heme structures, with diacetyldeuteroMb having the greatest nitrite binding affinity. Spectral deconvolution on the final product generated from the reaction between MbII and NO2- for the reconstituted Mbs indicates the formation of 1:1 MbIII and MbII-NO. The electronic changes induced by the -R groups on the 2,4-positions do not alter the stoichiometric ratio of the products, resembling wt Mb.",
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Modulating the nitrite reductase activity of globins by varying the heme substituents : Utilizing myoglobin as a model system. / Galinato, Mary Grace I.; Fogle, Robert S.; Stetz, Amanda; Galan, Jhenny F.

In: Journal of Inorganic Biochemistry, Vol. 154, 01.01.2016, p. 7-20.

Research output: Contribution to journalArticle

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T1 - Modulating the nitrite reductase activity of globins by varying the heme substituents

T2 - Utilizing myoglobin as a model system

AU - Galinato, Mary Grace I.

AU - Fogle, Robert S.

AU - Stetz, Amanda

AU - Galan, Jhenny F.

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AB - Globins, such as hemoglobin (Hb) and myoglobin (Mb), have gained attention for their ability to reduce nitrite (NO2-) to nitric oxide (NO). The molecular interactions that regulate this chemistry are not fully elucidated, therefore we address this issue by investigating one part of the active site that may control this reaction. Here, the effects of the 2,4-heme substituents on the nitrite reductase (NiR) reaction, and on the structures and energies of the ferrous nitrite intermediates, are investigated using Mb as a model system. This is accomplished by studying Mbs with hemes that have different 2,4-R groups, namely diacetyldeuteroMb (-acetyl), protoMb (wild-type (wt) Mb, -vinyl), deuteroMb (-H), and mesoMb (-ethyl). While trends on the natural charge on Fe and O-atom of bound nitrite are observed among the series of Mbs, the FeII-NPyr (Pyr = pyrrole) and FeII-NHis93 (His = histidine) bond lengths do not significantly change. Kinetic analysis shows increasing NiR activity as follows: diacetyldeuteroMb < wt Mb < deuteroMb < mesoMb. Nitrite binding energy calculations of the different MbII-nitrite conformations demonstrate the N-bound complexes to be more stable than the O-bound complexes for all the different types of heme structures, with diacetyldeuteroMb having the greatest nitrite binding affinity. Spectral deconvolution on the final product generated from the reaction between MbII and NO2- for the reconstituted Mbs indicates the formation of 1:1 MbIII and MbII-NO. The electronic changes induced by the -R groups on the 2,4-positions do not alter the stoichiometric ratio of the products, resembling wt Mb.

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