Resonance Raman studies of iron spin and axial coordination in distal pocket mutants of ferric myoglobin

D. Morikis, P. M. Champion, B. A. Springer, K. D. Egeberg, S. G. Sligar

Research output: Contribution to journalArticlepeer-review

Abstract

We have used resonance Raman spectroscopy to study 11 distal pocket mutants and the 'wild type' and native ferric sperm whale myoglobin. The characteristic Raman core-size markers ν4, ν3, ν2, and v10 are utilized to assign the spin and coordination state of each sample. It is demonstrated that replacements of the distal and proximal histidines can discriminate against H2O as a sixth ligand and favor a pentacoordinate Fe3+ atom. Soret absorption band blueshifts are correlated with the pentacoordinate heme environment. One E7 replacement (Arg) leads to an iron spin state change and produces a low spin species. The Glu and Ala mutations at position E11 leave the protein's spin and coordination unaltered. A laser-induced photoreduction effect is observed in all pentacoordinate mutants and seems to be correlated with the loss of the heme-bound water molecule.

Original languageEnglish (US)
Pages (from-to)12143-12145
Number of pages3
JournalJournal of Biological Chemistry
Volume265
Issue number21
StatePublished - 1990

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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