Analysis of powder and single crystal electron paramagnetic resonance spectra of deoxy myoglobins containing cobalt (II) proto-and mesoporphyrins IX at various microwave frequencies.

H. Hori, M. Ikeda-Saito, W. Froncisz, T. Yonetani

研究成果: Article査読

4 被引用数 (Scopus)

抄録

Artificial myoglobins (Mbs) substituted for protoheme with Co(II) proto-and mesoporphyrins IX (proto-and meso-CoMbs, respectively) were prepared. The principal values and eigenvectors of g tensors and the hyperfine coupling tensors of the paramagnetic Co(II) centers of their deoxy forms have been determined by single crystal EPR spectroscopy at 77 K in order to elucidate orientation and electronic structure of the prosthetic group in myoglobin. The orientation of the porphyrin plane of deoxy meso-CoMb were found to be identical to that of deoxy proto-CoMb. However, the in-plane hyperfine coupling constants of deoxy meso-CoMb were more anisotropic and larger than those of deoxy proto-CoMb, suggesting an increase in the electron spin density on the Co(II) ion upon the exchange of protoporphyrin IX with mesoprophyrin IX. Powder EPR spectra of these CoMbs, which were measured at S- and L-band microwave frequencies, exhibited well resolved 59Co hyperfine splittings and can be clearly interpreted by the use of the EPR parameters obtained from single crystal EPR measurements.

本文言語English
ページ(範囲)12368-12372
ページ数5
ジャーナルJournal of Biological Chemistry
258
20
出版ステータスPublished - 1983 10月 25

ASJC Scopus subject areas

  • 生化学
  • 分子生物学
  • 細胞生物学

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