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Pregled bibliografske jedinice broj: 675371

Differential coordination demands in Fe versus Mn water-soluble cationic metalloporphyrins translate into remarkably different aqueous redox chemistry and biology


Tovmasyan, Artak; Weitner, Tin; Sheng, Huaxin; Lu, Miaomiao; Rajić, Zrinka; Warner, David S.; Spasojević, Ivan; Reboucas, Julio S.; Benov, Ludmil; Batinić-Haberle, Ines
Differential coordination demands in Fe versus Mn water-soluble cationic metalloporphyrins translate into remarkably different aqueous redox chemistry and biology // Inorganic chemistry, 52 (2013), 10; 5677-5691 doi:10.1021/ic3012519 (međunarodna recenzija, članak, znanstveni)


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Naslov
Differential coordination demands in Fe versus Mn water-soluble cationic metalloporphyrins translate into remarkably different aqueous redox chemistry and biology

Autori
Tovmasyan, Artak ; Weitner, Tin ; Sheng, Huaxin ; Lu, Miaomiao ; Rajić, Zrinka ; Warner, David S. ; Spasojević, Ivan ; Reboucas, Julio S. ; Benov, Ludmil ; Batinić-Haberle, Ines

Izvornik
Inorganic chemistry (0020-1669) 52 (2013), 10; 5677-5691

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Mn pyridylporphyrin; Fe pyridylporphyrin

Sažetak
The different biological behavior of cationic Fe and Mn pyridylporphyrins in Escherichia coli and mouse studies prompted us to revisit and compare their chemistry. For that purpose, the series of ortho and meta isomers of Fe(III) mesotetrakis- N-alkylpyridylporphyrins, alkyl being methyl to n-octyl, were synthesized and characterized by elemental analysis, UV/vis spectroscopy, mass spectrometry, lipophilicity, protonation equilibria of axial waters, metal-centered reduction potential, E1/2 for MIIIP/MIIP redox couple (M = Fe, Mn, P = porphyrin), kcat for the catalysis of O2 •− dismutation, stability toward peroxide-driven porphyrin oxidative degradation (produced in the catalysis of ascorbate oxidation by MP), ability to affect growth of SODdeficient E. coli, and toxicity to mice. Electron-deficiency of the metal site is modulated by the porphyrin ligand, which renders Fe(III) porphyrins ≥5 orders of magnitude more acidic than the analogous Mn(III) porphyrins, as revealed by the pKa1 of axially coordinated waters. The 5 log units difference in the acidity between the Mn and Fe sites in porphyrin translates into the predominance of tetracationic (OH)(H2O)FeP complexes relative to pentacationic (H2O)2MnP species at pH ∼7.8. This is additionally evidenced in large differences in the E1/2 values of MIIIP/MIIP redox couples. The presence of hydroxo ligand labilizes trans-axial water which results in higher reactivity of Fe relative to Mn center. The differences in the catalysis of O2 •− dismutation (log kcat) between Fe and Mn porphyrins is modest, 2.5−5- fold, due to predominantly outer-sphere, with partial inner-sphere character of two reaction steps. However, the rate constant for the innersphere H2O2-based porphyrin oxidative degradation is 18-fold larger for (OH)(H2O)FeP than for (H2O)2MnP. The in vivo consequences of the differences between the Fe and Mn porphyrins were best demonstrated in SOD-deficient E. coli growth. On the basis of fairly similar log kcat(O2 •−) values, a very similar effect on the growth of SOD-deficient E. coli was anticipated by both metalloporphyrins. Yet, while (H2O)2MnTE-2-PyP5+ was fully efficacious at ≥20 μM, the Fe analogue (OH)(H2O)FeTE-2-PyP4+ supported SOD-deficient E. coli growth at as much as 200-fold lower doses in the range of 0.1−1 μM. Moreover the pattern of SOD-deficient E. coli growth was different with Mn and Fe porphyrins. Such results suggested a different mode of action of these metalloporphyrins. Further exploration demonstrated that (1) 0.1 μM (OH)(H2O)FeTE-2-PyP4+ provided similar growth stimulation as the 0.1 μM Fe salt, while the 20 μMMn salt provides no protection to E. coli ; and (2) 1 μM Fe porphyrin is fully degraded by 12 h in E. coli cytosol and growth medium, while Mn porphyrin is not. Stimulation of the aerobic growth of SOD-deficient E. coli by the Fe porphyrin is therefore due to iron acquisition. Our data suggest that in vivo, redox-driven degradation of Fe porphyrins resulting in Fe release plays a major role in their biological action. Possibly, iron reconstitutes enzymes bearing [4Fe-4S] clusters as active sites. Under the same experimental conditions, (OH)(H2O)FePs do not cause mouse arterial hypotension, whereas (H2O)2MnPs do, which greatly limits the application of Mn porphyrins in vivo.

Izvorni jezik
Engleski

Znanstvena područja
Kemija



POVEZANOST RADA


Profili:

Avatar Url Zrinka Rajić (autor)

Avatar Url Ines Batinić-Haberle (autor)

Avatar Url Tin Weitner (autor)

Citiraj ovu publikaciju

Tovmasyan, Artak; Weitner, Tin; Sheng, Huaxin; Lu, Miaomiao; Rajić, Zrinka; Warner, David S.; Spasojević, Ivan; Reboucas, Julio S.; Benov, Ludmil; Batinić-Haberle, Ines
Differential coordination demands in Fe versus Mn water-soluble cationic metalloporphyrins translate into remarkably different aqueous redox chemistry and biology // Inorganic chemistry, 52 (2013), 10; 5677-5691 doi:10.1021/ic3012519 (međunarodna recenzija, članak, znanstveni)
Tovmasyan, A., Weitner, T., Sheng, H., Lu, M., Rajić, Z., Warner, D., Spasojević, I., Reboucas, J., Benov, L. & Batinić-Haberle, I. (2013) Differential coordination demands in Fe versus Mn water-soluble cationic metalloporphyrins translate into remarkably different aqueous redox chemistry and biology. Inorganic chemistry, 52 (10), 5677-5691 doi:10.1021/ic3012519.
@article{article, year = {2013}, pages = {5677-5691}, DOI = {10.1021/ic3012519}, keywords = {Mn pyridylporphyrin, Fe pyridylporphyrin}, journal = {Inorganic chemistry}, doi = {10.1021/ic3012519}, volume = {52}, number = {10}, issn = {0020-1669}, title = {Differential coordination demands in Fe versus Mn water-soluble cationic metalloporphyrins translate into remarkably different aqueous redox chemistry and biology}, keyword = {Mn pyridylporphyrin, Fe pyridylporphyrin} }

Časopis indeksira:


  • Current Contents Connect (CCC)
  • Web of Science Core Collection (WoSCC)
    • Science Citation Index Expanded (SCI-EXP)
    • SCI-EXP, SSCI i/ili A&HCI
  • Scopus
  • MEDLINE


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