PUBLICATION
Structural and Kinetic Basis of Steroid 17α,20-Lyase Activity in Teleost Fish Cytochrome P450 17A1 and Its Absence in Cytochrome P450 17A2
- Authors
- Pallan, P.S., Nagy, L.D., Lei, L., Gonzalez, E., Kramlinger, V.M., Azumaya, C.M., Wawrzak, Z., Waterman, M.R., Guengerich, F.P., Egli, M.
- ID
- ZDB-PUB-141224-18
- Date
- 2015
- Source
- The Journal of biological chemistry 290(6): 3248-68 (Journal)
- Registered Authors
- Keywords
- X-ray crystallography, cytochrome P450, enzyme kinetics, pre-steady-state kinetics, steroidogenesis
- MeSH Terms
-
- Amino Acid Sequence
- Androstenes/pharmacology
- Animals
- Catalytic Domain*
- Kinetics
- Molecular Docking Simulation
- Molecular Sequence Data
- Progesterone/pharmacology
- Protein Binding
- Steroid 17-alpha-Hydroxylase/antagonists & inhibitors
- Steroid 17-alpha-Hydroxylase/chemistry*
- Steroid 17-alpha-Hydroxylase/metabolism
- Zebrafish
- Zebrafish Proteins/antagonists & inhibitors
- Zebrafish Proteins/chemistry*
- Zebrafish Proteins/metabolism
- PubMed
- 25533464 Full text @ J. Biol. Chem.
Citation
Pallan, P.S., Nagy, L.D., Lei, L., Gonzalez, E., Kramlinger, V.M., Azumaya, C.M., Wawrzak, Z., Waterman, M.R., Guengerich, F.P., Egli, M. (2015) Structural and Kinetic Basis of Steroid 17α,20-Lyase Activity in Teleost Fish Cytochrome P450 17A1 and Its Absence in Cytochrome P450 17A2. The Journal of biological chemistry. 290(6):3248-68.
Abstract
Cytochrome P450 (P450) 17A enzymes play a critical role in the oxidation of the steroids progesterone (Prog) and pregnenolone (Preg) to glucocorticoids and androgens. In mammals a single enzyme, P450 17A1, catalyzes both 17α-hydroxylation and a subsequent 17α,20-lyase reaction with both Prog and Preg. Teleost fish contain two 17A P450s: zebrafish P450 17A1 catalyzes both 17α-hydroxylation and lyase reactions with Prog and Preg, and P450 17A2 is more efficient in pregnenolone 17α-hydroxylation but does not catalyze the lyase reaction, even in the presence of cytochrome b5. P450 17A2 binds all substrates and products, although more loosely than P450 17A1. Pulse-chase and kinetic spectral experiments and modeling established that the 2-step P450 17A1 Prog oxidation is more distributive than the Preg reaction, i.e. 17α-OH product dissociates more prior to the lyase step. The drug orteronel selectively blocked the lyase reaction of P450 17A1, but only in the case of Prog. X-ray crystal structures of zebrafish P450 17A1 and 17A2 were obtained with the ligand abiraterone and, for P450 17A2, with Prog. Comparison of the two fish P450 17A-abiraterone structures with human P450 17A1 (DeVore, N. M., and Scott, E. E. (2013) Nature 482, 116-119) showed only a few differences near the active site, despite only ~50% identity among the three proteins. The P450 17A2 structure differed in four residues near the heme periphery. These residues may allow the proposed alternate ferric peroxide mechanism for the lyase reaction, or residues removed from the active site may allow conformations that lead to the lyase activity.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping