Conformational Change Induced by Putidaredoxin Binding to Ferrous CO-ligated Cytochrome P450cam Characterized by 2D IR Spectroscopy
Autor: | Edward J. Basom, Sashary Ramos, Megan C. Thielges |
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Rok vydání: | 2018 |
Předmět: |
0301 basic medicine
Conformational change endocrine system Cytochrome cytochrome P450 Population 010402 general chemistry 01 natural sciences Biochemistry Genetics and Molecular Biology (miscellaneous) Biochemistry digestive system 03 medical and health sciences Molecular Biosciences education infrared spectroscopy Molecular Biology lcsh:QH301-705.5 Original Research chemistry.chemical_classification education.field_of_study biology Effector Chemistry Protein dynamics energy landscape Cytochrome P450 Energy landscape 0104 chemical sciences 030104 developmental biology Enzyme lcsh:Biology (General) protein dynamics biology.protein Biophysics putidaredoxin 2D IR spectroscopy |
Zdroj: | Frontiers in Molecular Biosciences Frontiers in Molecular Biosciences, Vol 5 (2018) |
ISSN: | 2296-889X |
Popis: | The importance of conformational dynamics to protein function is now well-appreciated. An outstanding question is whether they are involved in the effector role played by putidaredoxin (Pdx) in its reduction of the O2 complex of cytochrome P450cam (P450cam), an archetypical member of the cytochrome P450 superfamily. Recent studies have reported that binding of Pdx induces a conformational change from a closed to an open state of ferric P450cam, but a similar conformational change does not appear to occur for the ferrous, CO-ligated enzyme. To better understand the effector role of Pdx when binding the ferrous, CO-ligated P450cam, we applied 2D IR spectroscopy to compare the conformations and dynamics of the wild-type (wt) enzyme in the absence and presence of Pdx, as well as of L358P P450cam (L358P), which has served as a putative model for the Pdx complex. The CO vibrations of the Pdx complex and L358P report population of two conformational states in which the CO experiences distinct environments. The dynamics among the CO frequencies indicate that the energy landscape of substates within one conformation are reflective of the closed state of P450cam, and for the other conformation, differ from the free wt enzyme, but are equivalent between the Pdx complex and L358P. The two states co-populated by the Pdx complex are postulated to reflect a loosely bound encounter complex and a more tightly bound state, as is commonly observed for the dynamic complexes of redox partners. Significantly, this study shows that the binding of Pdx to ferrous, CO-ligated P450cam does perturb the conformational ensemble in a way that might underlie the effector role of Pdx. |
Databáze: | OpenAIRE |
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