Abstract
Ferrochelatase catalyzes Fe2+ insertion into porphyrins, and is inhibited by Hg2+. Resonance Raman spectra of mesoporphyrin IX show that binding to ferrochelatase restricts the conformation of the propionate side chains, but does not perturb the ring conformation. However, a pronounced perturbation is seen in the ternary complex with Hg2+. Several additional RR bands are activated, including some arising from [R-active vibrations, establishing loss of an effective symmetry center. Out-of-plane modes appear in the low frequency region. The strongest of these bands, γ5 and γ6, correspond to pyrrole tilting vibrations, which are in the same symmetry class as a doming distortion of the porphyrin. All four pyrrole N atoms are pointing toward the same side of the porphyrin plane, a geometry expected to facilitate Fe2+ insertion. This distortion is proposed to result from occupation of a metal-binding site, proximate to the prophyrin, which promotes insertion of Fe2+, while occupation by Hg2+ is inhibitory.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 12170-12174 |
| Number of pages | 5 |
| Journal | Journal of the American Chemical Society |
| Volume | 119 |
| Issue number | 50 |
| DOIs | |
| State | Published - Dec 17 1997 |
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ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Biochemistry
- Colloid and Surface Chemistry
Cite this
Resonance Raman spectra of ferrochelatase reveal porphyrin distortion upon metal binding. / Blackwood, Milton E.; Rush, Thomas S.; Medlock, Amy Elizabeth; Dailey, Harry A.; Spiro, Thomas G.
In: Journal of the American Chemical Society, Vol. 119, No. 50, 17.12.1997, p. 12170-12174.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Resonance Raman spectra of ferrochelatase reveal porphyrin distortion upon metal binding
AU - Blackwood, Milton E.
AU - Rush, Thomas S.
AU - Medlock, Amy Elizabeth
AU - Dailey, Harry A.
AU - Spiro, Thomas G.
PY - 1997/12/17
Y1 - 1997/12/17
N2 - Ferrochelatase catalyzes Fe2+ insertion into porphyrins, and is inhibited by Hg2+. Resonance Raman spectra of mesoporphyrin IX show that binding to ferrochelatase restricts the conformation of the propionate side chains, but does not perturb the ring conformation. However, a pronounced perturbation is seen in the ternary complex with Hg2+. Several additional RR bands are activated, including some arising from [R-active vibrations, establishing loss of an effective symmetry center. Out-of-plane modes appear in the low frequency region. The strongest of these bands, γ5 and γ6, correspond to pyrrole tilting vibrations, which are in the same symmetry class as a doming distortion of the porphyrin. All four pyrrole N atoms are pointing toward the same side of the porphyrin plane, a geometry expected to facilitate Fe2+ insertion. This distortion is proposed to result from occupation of a metal-binding site, proximate to the prophyrin, which promotes insertion of Fe2+, while occupation by Hg2+ is inhibitory.
AB - Ferrochelatase catalyzes Fe2+ insertion into porphyrins, and is inhibited by Hg2+. Resonance Raman spectra of mesoporphyrin IX show that binding to ferrochelatase restricts the conformation of the propionate side chains, but does not perturb the ring conformation. However, a pronounced perturbation is seen in the ternary complex with Hg2+. Several additional RR bands are activated, including some arising from [R-active vibrations, establishing loss of an effective symmetry center. Out-of-plane modes appear in the low frequency region. The strongest of these bands, γ5 and γ6, correspond to pyrrole tilting vibrations, which are in the same symmetry class as a doming distortion of the porphyrin. All four pyrrole N atoms are pointing toward the same side of the porphyrin plane, a geometry expected to facilitate Fe2+ insertion. This distortion is proposed to result from occupation of a metal-binding site, proximate to the prophyrin, which promotes insertion of Fe2+, while occupation by Hg2+ is inhibitory.
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U2 - 10.1021/ja971619c
DO - 10.1021/ja971619c
M3 - Article
AN - SCOPUS:2642621590
VL - 119
SP - 12170
EP - 12174
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 50
ER -