Cytochromes P450 and drug discovery
Introduction
Cytochromes P450 (CYP) comprise a superfamily of haem-containing enzymes which catalyze the molecular scission of atmospheric oxygen and are distributed across the kingdoms of life [1••]. New CYP sequences are being added to the current list of >6500 each day (http://drnelson.utmem.edu/CytochromeP450.html; http://p450.antibes.inra.fr; http://Arabidopsis-P450.biotec.uiuc.edu). CYP monooxygenases have pivotal roles in primary and secondary metabolic pathways. They have long been of interest because of their extraordinary ability to introduce atmospheric oxygen into non-activated carbon-hydrogen bonds, showing exceptionally high degrees of regio-selectivity and stereo-selectivity. In general, one oxygen atom is incorporated into the substrate molecule, usually a hydrocarbon, and the other oxygen atom is reduced to a water molecule. The basic CYP enzymatic reactions include C-hydroxylation, heteroatom oxygenation, heteroatom release (dealkylation), epoxide formation and group migration (Figure 1). However, in recent years a number of more complex CYP reactions have also been described and these include chlorine oxygenation, aromatic dehalogenation, dimer formation, ring coupling, ring formation, ring contraction and oxidative aryl migration (Figure 1; [2]). All CYPs use NAD(P)H as a source of electrons for the catalysis of dioxygen molecular scission and a redox partner(s) (usually NADPH cytochrome P450 reductase for eukaryotic CYPs and a ferredoxin and a ferredoxin reductase for prokaryotic CYPs) is required to transfer the reducing equivalents to the CYP haem Fe for catalysis.
The role of this review is to provide a summary of the most recent advances in our knowledge and application of CYPs in drug discovery. To this end, the review will summarize the roles of CYPs as drug targets as well as the roles they play in the biosynthesis of drugs (Figure 2). A very large body of information on the biology of mammalian CYPs in drug metabolism already exists and we direct the reader to the following article for expansive information in this area [3•].
Section snippets
Current strategies for inhibiting CYPs for clinical application
Examples of the use of CYPs as drug targets are rare in medicine. Of the human CYPs, only CYP19A1 (aromatase) has a real status as a drug target. This is the enzyme that converts androgens to oestrogens, and inhibitors such as anastrozole, exemestane and letrozole (Figure 3a, [4]) have efficacy in oestrogen-dependent tumours (breast, endometrium). The primary drawback to the use of CYP19A1 inhibitors in clinical therapy is the problem of achieving direct specificity for tumours, in that CYP19A1
Exploitation of microbial CYPs in drug discovery
The genomic era has revealed that CYP enzymes catalyze a large proportion of the most complex and chemically challenging steps in the biosynthesis of many natural products used in medicine today. Given the diversity of reactions catalysed by CYPs, only a few examples exist in industry where CYP enzymes have been exploited. The history goes back at least 50 years, for example the conversion of progesterone to cortisone through 11α-hydroxylation by Rhizopus cultures [16]. Several pharmaceutical
Strategies for drug discovery involved CYP bioengineering
Historically, natural product research in drug discovery has been a process of pharmacognosy, that is searching various extracts of plants, soil bacteria, ocean extracts, among others. However, knowledge about biosynthetic pathways allows for new strategies.
Conclusions and future perspectives
CYP biodiversity is presenting an exciting opportunity both to screen pathogens containing CYPs to be potential drug targets and to dissect CYP function to reveal roles in drug biosynthesis which are then open to manipulation in the hope of generating new drugs. In particular new genome sequencing projects have revealed many CYPs linked to antibiotic producing gene clusters both from the terrestrial and aquatic environments and such information will provide solid foundations in the drug
References and recommended reading
Papers of particular interest, published within the annual period of review, have been highlighted as:
• of special interest
•• of outstanding interest
Acknowledgements
This work was supported by National Institutes of Health Grants R01GM69970, R37 CA090426 and P30ES00267 and by a Leverhulme Trust Research Fellowship.
References (42)
Human cytochrome P450 enzymes
- et al.
Primary structure of P450 lanosterol demethylase gene from Sacchaaromyces cerevisiae
DNA
(1987) - et al.
CYP51 from Trypanosoma cruzi: a phyla-specific residue in the B’ helix defines substrate preferences of sterol 14α-demethylase
J Biol Chem
(2006) - et al.
Crystal structure of OxyC, a cytochrome P450 implicated in an oxidative C–C coupling reaction during vancomycin biosynthesis
J Biol Chem
(2003) - et al.
Oxidative phenol coupling reactions catalyzed by OxyB: A cytochrome P450 from the vancomycin producting organisms. Implications for vancomycin biosynthesis
J Am Chem Soc
(2007) - et al.
Cytochromes P450s in plants
- et al.
Plant cytochromes P450: tools for pharmacology, plant protection and phytoremediation
Curr Opin Biotechnol
(2003) - et al.
Engineering Escherichia coli for production of functionalized terpenoids using plant P450s
Nat Chem Biol
(2007) - et al.
Bindings of two flaviolin substrate molecules, oxidative coupling, and crystal structure of Streptomyces coelicolor A3(2) cytochrome P450 158A2
J Biol Chem
(2005)
Cytochromes P450 as versatile biocatalysts
J Biotechnol
Update on the use of aromatase inhibitors in breast cancer
Exp Opin Pharmacother
Drug-drug interactions for UDP-glucuronosyltransferase substrates: a pharmacokinetic explanation for typically observed low exposure (AUCi/AUC) ratios
Drug Metab Dispos
Synthetic inhibitors of cytochrome P-450 2A6: inhibitory activity, difference spectra, mechanism of inhibition, and protein cocrystallization
J Med Chem
Clinical importance of the cytochromes P450
Lancet
From the design to the clinical application of thromboxane modulators
Curr Pharm Des
Recent progress in CYP51 research focusing on its unique evolutionary and functional characteristics as a diversozyme P450
Front Biosci
The preponderance of P450s in the Mycobacterium tuberculosis genome
Trends Microbiol
Genes required for mycobacterial growth defined by high density mutagenesis
Mol Microbiol
Identification of mycobacterial genes that alter growth and pathology in macrophages and in mice
J Infect Dis
Drugs and drug resistance in African trypanosomiasis
Drug Resist Updat
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