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Metal binding to Bacillus subtilis ferrochelatase and interaction between metal sites.

Lecerof, David LU ; Fodje, Michel LU ; Alvarez León, Román; Olsson, Ulf LU ; Hansson, Andreas LU ; Sigfridsson, Emma; Ryde, Ulf LU ; Hansson, Mats LU and Al-Karadaghi, Salam LU (2003) In Journal of Biological Inorganic Chemistry 8(4). p.452-458
Abstract
Ferrochelatase, the terminal enzyme in heme biosynthesis, catalyses metal insertion into protoporphyrin IX. The location of the metal binding site with respect to the bound porphyrin substrate and the mode of metal binding are of central importance for understanding the mechanism of porphyrin metallation. In this work we demonstrate that Zn2+, which is commonly used as substrate in assays of the ferrochelatase reaction, and Cd2+, an inhibitor of the enzyme, bind to the invariant amino acids His183 and Glu264 and water molecules, all located within the porphyrin binding cleft. On the other hand, Mg2+, which has been shown to bind close to the surface at 7 Å from His183, was largely absent from its site. Activity measurements demonstrate... (More)
Ferrochelatase, the terminal enzyme in heme biosynthesis, catalyses metal insertion into protoporphyrin IX. The location of the metal binding site with respect to the bound porphyrin substrate and the mode of metal binding are of central importance for understanding the mechanism of porphyrin metallation. In this work we demonstrate that Zn2+, which is commonly used as substrate in assays of the ferrochelatase reaction, and Cd2+, an inhibitor of the enzyme, bind to the invariant amino acids His183 and Glu264 and water molecules, all located within the porphyrin binding cleft. On the other hand, Mg2+, which has been shown to bind close to the surface at 7 Å from His183, was largely absent from its site. Activity measurements demonstrate that Mg2+ has a stimulatory effect on the enzyme, lowering KM for Zn2+ from 55 to 24 µM. Changing one of the Mg2+ binding residues, Glu272, to serine abolishes the effect of Mg2+. It is proposed that prior to metal insertion the metal may form a sitting-atop (SAT) complex with the invariant His-Glu couple and the porphyrin. Metal binding to the Mg2+ site may stimulate metal release from the protein ligands and its insertion into the porphyrin. (Less)
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Contribution to journal
publication status
published
subject
in
Journal of Biological Inorganic Chemistry
volume
8
issue
4
pages
452 - 458
publisher
Springer
external identifiers
  • pmid:12761666
  • wos:000183036300009
  • scopus:0037613378
ISSN
1432-1327
DOI
language
English
LU publication?
yes
id
726d88bd-5298-4a1c-8615-a5b487334ca0 (old id 128485)
date added to LUP
2007-07-06 10:07:08
date last changed
2018-05-29 10:59:24
@article{726d88bd-5298-4a1c-8615-a5b487334ca0,
  abstract     = {Ferrochelatase, the terminal enzyme in heme biosynthesis, catalyses metal insertion into protoporphyrin IX. The location of the metal binding site with respect to the bound porphyrin substrate and the mode of metal binding are of central importance for understanding the mechanism of porphyrin metallation. In this work we demonstrate that Zn2+, which is commonly used as substrate in assays of the ferrochelatase reaction, and Cd2+, an inhibitor of the enzyme, bind to the invariant amino acids His183 and Glu264 and water molecules, all located within the porphyrin binding cleft. On the other hand, Mg2+, which has been shown to bind close to the surface at 7 Å from His183, was largely absent from its site. Activity measurements demonstrate that Mg2+ has a stimulatory effect on the enzyme, lowering KM for Zn2+ from 55 to 24 µM. Changing one of the Mg2+ binding residues, Glu272, to serine abolishes the effect of Mg2+. It is proposed that prior to metal insertion the metal may form a sitting-atop (SAT) complex with the invariant His-Glu couple and the porphyrin. Metal binding to the Mg2+ site may stimulate metal release from the protein ligands and its insertion into the porphyrin.},
  author       = {Lecerof, David and Fodje, Michel and Alvarez León, Román and Olsson, Ulf and Hansson, Andreas and Sigfridsson, Emma and Ryde, Ulf and Hansson, Mats and Al-Karadaghi, Salam},
  issn         = {1432-1327},
  language     = {eng},
  number       = {4},
  pages        = {452--458},
  publisher    = {Springer},
  series       = {Journal of Biological Inorganic Chemistry},
  title        = {Metal binding to Bacillus subtilis ferrochelatase and interaction between metal sites.},
  url          = {http://dx.doi.org/},
  volume       = {8},
  year         = {2003},
}