Evidence that a formyl-substituted iron porphyrin is the prosthetic group of myeloperoxidase: Magnetic circular dichroism similarity of the peroxidase to Spirographis heme-reconstituted myoglobin

Masanori Sono, Alma M. Brachte, Ann M. Huff, Masao Ikeda-Saito, John H. Dawson

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

To probe the identity of the active site hemetype prosthetic group of myeloperoxidase, whose structure has not been established unambiguously [proposed structures are (i) a chlorin (dihydroporphyrin) or (ii) a formyl-substituted porphyrin such as present in heme a], Spirographis heme (2-formyl-4-vinyldeuteroheme IX) has been incorporated into apo-myoglobin as a possible iron porphyrin model. Comparison of parallel derivatives of these two green proteins with magnetic circular dichroism spectroscopy reveals considerable similarities between several derivatives of these proteins, including the pyridine hemochromogen, the native ferric, ferrous-oxy, and ferrous-CO forms. In contrast, the magnetic circular dichroism spectra of available iron chlorin (octaethylchlorin) model complexes in analogous ligation and oxidation states do not show any significant spectral similarities to myeloperoxidase. This finding provides important evidence in favor of a formyl-substituted porphyrin as the structure of the prosthetic group macrocycle of myeloperoxidase.

Original languageEnglish
Pages (from-to)11148-11152
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume88
Issue number24
DOIs
Publication statusPublished - 1991

Keywords

  • 2-formyl-4-vinyldeuteroheme IX
  • Green heme proteins
  • Iron chlorin complexes
  • Sign-inverted magnetic circular dichroism spectra

ASJC Scopus subject areas

  • General

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