Journal article
The Endogenous Calcium Ions of Horseradish Peroxidase C Are Required to Maintain the Functional Nonplanarity of the Heme
Biophysical journal, v 84(4), pp 2542-2552
Apr 2003
PMID: 12668462
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Horseradish peroxidase C (HRPC) binds 2 mol calcium per mol of enzyme with binding sites located distal and proximal to the heme group. The effect of calcium depletion on the conformation of the heme was investigated by combining polarized resonance Raman dispersion spectroscopy with normal coordinate structural decomposition analysis of the hemes extracted from models of Ca
2+
-bound and Ca
2+
-depleted HRPC generated and equilibrated using molecular dynamics simulations. Results show that calcium removal causes reorientation of heme pocket residues. We propose that these rearrangements significantly affect both the in-plane and out-of-plane deformations of the heme. Analysis of the experimental depolarization ratios are clearly consistent with increased B
1g
- and B
2g
-type distortions in the Ca
2+
-depleted species while the normal coordinate structural decomposition results are indicative of increased planarity for the heme of Ca
2+
-depleted HRPC and of significant changes in the relative contributions of three of the six lowest frequency deformations. Most noteworthy is the decrease of the strong saddling deformation that is typical of all peroxidases, and an increase in ruffling. Our results confirm previous work proposing that calcium is required to maintain the structural integrity of the heme in that we show that the preferred geometry for catalysis is lost upon calcium depletion.
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Details
- Title
- The Endogenous Calcium Ions of Horseradish Peroxidase C Are Required to Maintain the Functional Nonplanarity of the Heme
- Creators
- Monique Laberge - Institute of Biophysics and Radiation Biology, Semmelweis University, Puskin u. 9, Budapest H-1088, Hungary; andQing Huang - Institute of Biophysics and Radiation Biology, Semmelweis University, Puskin u. 9, Budapest H-1088, Hungary; andReinhard Schweitzer-Stenner - Institute of Biophysics and Radiation Biology, Semmelweis University, Puskin u. 9, Budapest H-1088, Hungary; andJudit Fidy - Institute of Biophysics and Radiation Biology, Semmelweis University, Puskin u. 9, Budapest H-1088, Hungary; and
- Publication Details
- Biophysical journal, v 84(4), pp 2542-2552
- Publisher
- Biophysical Society
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Chemistry
- Web of Science ID
- WOS:000183123100040
- Scopus ID
- 2-s2.0-0037379807
- Other Identifier
- 991014878225304721
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Biophysics