Calcium-Dependent Heme Structure in the Reduced Forms of the Bacterial Cytochrome c Peroxidase from Paracoccus pantotrophus

@article{citeulike:2732440, abstract = {Abstract: This work reports for the first time a resonance Raman study of the mixed-valence and fully reduced forms of Paracoccus pantotrophus bacterial cytochrome c peroxidase. The spectra of the active mixed-valence enzyme show changes in the structure of the ferric peroxidatic heme compared to the fully oxidized enzyme; these differences are observed upon reduction of the electron-transferring heme and upon full occupancy of the calcium site. For the mixed-valence form in the absence of Ca2+, the peroxidatic heme is six-coordinate and low-spin on the basis of the frequencies of the structure-sensitive Raman lines: the enzyme is inactive. With added Ca2+, the peroxidatic heme is five-coordinate high-spin and active. The calcium-dependent spectral differences indicate little change in the conformation of the ferrous electron-transferring heme, but substantial changes in the conformation of the ferric peroxidatic heme. Structural changes associated with Ca2+ binding are indicated by spectral differences in the structure-sensitive marker lines, the out-of-plane low-frequency macrocyclic modes, and the vibrations associated with the heme substituents of that heme. The Ca2+-dependent appearance of a strong ³15 saddling-symmetry mode for the mixed-valence form is consistent with a strong saddling deformation in the active peroxidatic heme, a feature seen in the Raman spectra of other peroxidases. For the fully reduced form in the presence of Ca2+, the resonance Raman spectra show that the peroxidatic heme remains high-spin.}, address = {REQUIMTE/CQFB, Departamento de Qui
mica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, Nanomaterials Sciences Department, Sandia National Laboratories, Albuquerque, New Mexico 87185-1349, Department of Chemistry, University of Georgia, Athens, Georgia 30602-2556, and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Summerhall, Edinburgh EH9 1QH, U.K.}, author = {Pauleta, Sofia R. and Lu, Yi and Goodhew, Celia F. and Moura, Isabel and Pettigrew, Graham W. and Shelnutt, John A. }, citeulike-article-id = {2732440}, doi = {10.1021/bi702486d}, journal = {Biochemistry}, keywords = {calcium, cytochrome, haem, paracoccus, peroxidase, structure}, month = {April}, posted-at = {2008-04-29 09:21:09}, priority = {2}, title = {Calcium-Dependent Heme Structure in the Reduced Forms of the Bacterial Cytochrome c Peroxidase from Paracoccus pantotrophus}, url = {http://dx.doi.org/10.1021/bi702486d}, year = {2008} }

TY - JOUR ID - citeulike:2732440 L3 - citeulike-article-id:2732440 TI - Calcium-Dependent Heme Structure in the Reduced Forms of the Bacterial Cytochrome c Peroxidase from Paracoccus pantotrophus JF - Biochemistry AD - REQUIMTE/CQFB, Departamento de Qui
mica, Faculdade de Ciencias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal, Nanomaterials Sciences Department, Sandia National Laboratories, Albuquerque, New Mexico 87185-1349, Department of Chemistry, University of Georgia, Athens, Georgia 30602-2556, and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Summerhall, Edinburgh EH9 1QH, U.K. N2 - Abstract: This work reports for the first time a resonance Raman study of the mixed-valence and fully reduced forms of Paracoccus pantotrophus bacterial cytochrome c peroxidase. The spectra of the active mixed-valence enzyme show changes in the structure of the ferric peroxidatic heme compared to the fully oxidized enzyme; these differences are observed upon reduction of the electron-transferring heme and upon full occupancy of the calcium site. For the mixed-valence form in the absence of Ca2+, the peroxidatic heme is six-coordinate and low-spin on the basis of the frequencies of the structure-sensitive Raman lines: the enzyme is inactive. With added Ca2+, the peroxidatic heme is five-coordinate high-spin and active. The calcium-dependent spectral differences indicate little change in the conformation of the ferrous electron-transferring heme, but substantial changes in the conformation of the ferric peroxidatic heme. Structural changes associated with Ca2+ binding are indicated by spectral differences in the structure-sensitive marker lines, the out-of-plane low-frequency macrocyclic modes, and the vibrations associated with the heme substituents of that heme. The Ca2+-dependent appearance of a strong ³15 saddling-symmetry mode for the mixed-valence form is consistent with a strong saddling deformation in the active peroxidatic heme, a feature seen in the Raman spectra of other peroxidases. For the fully reduced form in the presence of Ca2+, the resonance Raman spectra show that the peroxidatic heme remains high-spin. KW - calcium KW - cytochrome KW - haem KW - paracoccus KW - peroxidase KW - structure AU - Pauleta, Sofia AU - Lu, Yi AU - Goodhew, Celia AU - Moura, Isabel AU - Pettigrew, Graham AU - Shelnutt, John PY - 2008/04/29/ UR - http://dx.doi.org/10.1021/bi702486d ER -