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Biodiversity of P-450 Monooxygenase: Cross-Talk

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Cytochrome P450: Oxygen activation and biodiversty 1 Biodiversity of P-450 monooxygenase: Cross-talk between chemistry and biology Heme Fe(II)-CO complex 450 nm, different from those of hemoglobin and other heme proteins 410-420 nm. Cytochrome Pigment of 450 nm Cytochrome P450 CYP3A4…. 2 High Energy: Ultraviolet (UV) Low Energy: Infrared (IR) Soret band 420 nm or g-band Mb Fe(II) ---------- Mb Fe(II) + CO - - - - - - - Visible region Visible bands Q bands a-band, b-band b a 3 H2O/OH- O2 CO Fe(III) Fe(II) Fe(II) Fe(II) Soret band at 420 nm His His His His metHb deoxy Hb Oxy Hb Carbon monoxy Hb metMb deoxy Mb Oxy Mb Carbon monoxy Mb H2O/Substrate O2-Substrate CO Substrate Soret band at 450 nm Fe(III) Fe(II) Fe(II) Fe(II) Cytochrome P450 Cys Cys Cys Cys Active form 4 Monooxygenase Reactions by Cytochromes P450 (CYP) + + RH + O2 + NADPH + H → ROH + H2O + NADP RH: Hydrophobic (lipophilic) compounds, organic compounds, insoluble in water ROH: Less hydrophobic and slightly soluble in water. Drug metabolism in liver ROH + GST → R-GS GST: glutathione S-transferase ROH + UGT → R-UG UGT: glucuronosyltransferaseGlucuronic acid Insoluble compounds are converted into highly hydrophilic (water soluble) compounds. 5 Drug metabolism at liver: Sleeping pill, pain killer (Narcotic), carcinogen etc. Synthesis of steroid hormones (steroidgenesis) at adrenal cortex, brain, kidney, intestine, lung, Animal (Mammalian, Fish, Bird, Insect), Plants, Fungi, Bacteria 6 NSAID: non-steroid anti-inflammatory drug 7 8 9 10 11 Cytochrome P450: Cysteine-S binding to Fe(II) heme is important for activation of O2. Cytochrome c, Cytochrome b5: Electron-transfer relating heme proteins. Myoglobin and hemoglobin: Histidine-midazole binding to Fe(II) heme is important for O2 storage and O2 carrier, respectively. 14 NADPH-P450 Reductase Difference spectra: substrate binding 450 nm Shunt reaction NADPH-P450 Reductase 15 R: substrate R: substrate Shunt reaction R: substrate R: substrate R: substrate 16 17 Family Function Members Names CYP1 drug and steroid (especially estrogen) metabolism 3 subfamilies, 3 genes, 1 pseudogene CYP1A1, CYP1A2, CYP1B1 CYP2 drug and steroid metabolism 13 subfamilies, 16 genes, 16 pseudogenes CYP2A6, CYP2A7, CYP2A13, CYP2B6, CYP2C8, CYP2C9, CYP2C18, CYP2C19, CYP2D6, CYP2E1, CYP2F1, CYP2J2, CYP2R1, CYP2S1, CYP2U1, CYP2W1 CYP3 drug and steroid (including testosterone) metabolism 1 subfamily, 4 genes, 2 pseudogenes CYP3A4, CYP3A5, CYP3A7, CYP3A43 CYP4 arachidonic acid or fatty acid metabolism 6 subfamilies, 12 genes, 10 pseudogenes CYP4A11, CYP4A22, CYP4B1, CYP4F2, CYP4F3, CYP4F8, CYP4F11, CYP4F12, CYP4F22, CYP4V2, CYP4X1, CYP4Z1 CYP5 thromboxane A2 synthase 1 subfamily, 1 gene CYP5A1 CYP7 bile acid biosynthesis 7-alpha hydroxylase of steroid nucleus 2 subfamilies, 2 genes CYP7A1, CYP7B1 CYP8 varied2 subfamilies, 2 genes CYP8A1 (prostacyclin synthase), CYP8B1 (bile acid biosynthesis) CYP11 steroid biosynthesis 2 subfamilies, 3 genes CYP11A1, CYP11B1, CYP11B2 CYP17 steroid biosynthesis, 17-alpha hydroxylase 1 subfamily, 1 gene CYP17A1 CYP19steroid biosynthesis: aromatase synthesizes estrogen 1 subfamily, 1 gene CYP19A1 CYP20 unknown function 1 subfamily, 1 gene CYP20A1 CYP21 steroid biosynthesis 2 subfamilies, 1 gene, 1 pseudogene CYP21A2 CYP24 vitamin D degradation 1 subfamily, 1 gene CYP24A1 CYP26 retinoic acid hydroxylase 3 subfamilies, 3 genes CYP26A1, CYP26B1, CYP26C1 CYP27 varied 3 subfamilies, 3 genes CYP27A1 (bile acid biosynthesis), CYP27B1 (vitamin D3 1-alpha hydroxylase, activates vitamin D3), CYP27C1 (unknown function) CYP39 7-alpha hydroxylation of 24-hydroxycholesterol 1 subfamily, 1 gene CYP39A1 CYP46 cholesterol 24-hydroxylase 1 subfamily, 1 gene CYP46A1 CYP51 cholesterol biosynthesis 1 subfamily, 1 gene, 3 pseudogenes CYP51A1 (lanosterol 14-alpha demethylase) 18 Fish, Crab and Bird P450s Those animals are used for monitoring environmental contamination/pollution with using liver. 19 One of PCBs Environmental chemicals: P450’s substrates Expression of P-glycoprotein and PCB, chloroethane, benzo[A] pyrene cytochrome P450 1A in intertidal fish Herbicides, Insecticides (Anoplarchus purpurescens) exposed to environmental contaminants 20 Arctic Monitoring and Assessment Programme 21 Insects Alkaloids are toxic for insects. Growth regulation: molting Sex, Alarm, Group hormones Those are natural products of plants and used for insecticides. P450 is involved in pheromone synthesis, fighting against plant toxin, and fighting against insecticides. 22 An insect-specific P450 oxidative decarbonylase for cuticular hydrocarbon biosynthesis Proc. Nat. Acad. Sci. U.S.A. 109, 14858 (2012) Abstract Insects use hydrocarbons as cuticular waterproofing agents and as contact pheromones. Although their biosynthesis from fatty acyl precursors is well established, the last step of hydrocarbon biosynthesis from long-chain fatty aldehydes has remained mysterious. We show here that insects use a P450 enzyme of the CYP4G family to oxidatively produce hydrocarbons from aldehydes. Oenocyte-directed RNAi knock-down of Drosophila CYP4G1 or NADPH-cytochrome P450 reductase results in flies deficient in cuticular hydrocarbons, highly susceptible to desiccation, and with reduced viability upon adult emergence. The heterologously expressed enzyme converts C18-trideuterated octadecanal to C17- trideuterated heptadecane, showing that the insect enzyme is an oxidative decarbonylase that catalyzes the cleavage of long-chain aldehydes to hydrocarbons with the release of carbon dioxide. This process is unlike cyanobacteria that use a nonheme diiron decarbonylase to make alkanes from aldehydes with the release of formate. The unique and highly conserved insect CYP4G enzymes are a key evolutionary innovation that allowed their colonization of land. 23 Fig. 1. Hydrocarbon biosynthesis from very long-chain fatty acyl thioesters in cyanobacteria and in insects. The decarbonylase enzyme from plants has not been formally identified to date. ACP, acyl carrier protein. 24 Fig. 2. Colocalization of CYP4G1 and CPR in oenocytes. Whole-mount immunocytochemistry of NADPH-cytochrome P450 reductase (Upper Left, FITC) and CYP4G1 (Upper Right, Alexa 633) in Drosophila abdomens. Confocal microscopy shows the bands of large oenocytes where both enzymes are colocalized (Lower Right, yellow). Lower Left is the bright field image showing bristles for scale. 25 Fig. 4. Desiccation resistance of adult D. melanogaster. The time course of adult male (▲) and female (●) fly survival in dry conditions is shown for control insects (full lines) and for flies with RNAi-suppressed CYP4G1 expression (stippled lines). n = 20 for each condition. 26 27 Butterfly •Citrus (lemon, orange) Leaves. Strong flavor. Flavonoids. •Green caterpillar of the Lime Butterfly can eat citrus leaves. •P450s of butterfly metabolize the compounds. 28 Plants Synthesis of natural products 29 Plants Fights against insects and herbicides 30 31 Flower color was changed by manipulation of P450 genes: Rose Blue Rose: Suntory 32 Flower color was changed by manipulation of P450 genes: Petunia 33 Bacterial P450s Cytochrome P450cam (CYP101) originally from Pseudomonas putida has been used as a model for many cytochromes P450 and was the first cytochrome P450 three-dimensional protein structure solved by X-ray crystallography. Very stable, easy to analyze, thus used as a model for P450 catalysis. Mycobacterium tuberculosis P450s: Inhibitors : structure and functions 34 Biomimicry in reverse. The natural P450 monooxygenase enzyme catalyzes C–H bond oxidation. Through judicious choice of enzyme and substrate followed by directed evolution, Coelho et al. have re-engineered this protein to perform a different catalytic reaction, namely cyclopropanation. Science 339, 283 (2013) 35 Olefin Cyclopropanation via Carbene Transfer Catalyzed by Engineered Cytochrome P450 Enzymes Transition metal–catalyzed transfers of carbenes, nitrenes, and oxenes are powerful methods for functionalizing C=C and C–H bonds. Nature has evolved a diverse toolbox for oxene transfers, as exemplified by the myriad monooxygenation reactions catalyzed by cytochrome P450 enzymes. The isoelectronic carbene transfer to olefins, a widely used C–C bond–forming reaction in organic synthesis, has no biological counterpart. Here we report engineered variants of cytochrome P450BM3 that catalyze highly diastereo- and enantioselective cyclopropanation of styrenes from diazoester reagents via putative carbene transfer. This work highlights the capacity to adapt existing enzymes for the catalysis of synthetically important reactions not previously observed in nature. Science 339, 307 (2013) 36 Science 339, 307 (2013) Fig. 1 (Left) Canonical mode of reactivity of cytochrome P450s. Monooxygenation of olefins and C-H bonds to epoxides and alcohols catalyzed by the ferryl porphyrin radical intermediate (compound I). (Right) Artificial mode of formal carbene transfer activity of cytochrome P450s, using diazoester reagents as carbene precursors. 37 Oxygen deprivation followed by reoxygenation causes pathological responses in many disorders, including ischemic stroke, heart attacks, and reperfusion injury. Key aspects of ischemia-reperfusion can be modeled by a Caenorhabditis elegans behavior, the O2-ON response, which is suppressed by hypoxic preconditioning or inactivation of the O2-sensing HIF (hypoxia-inducible factor) hydroxylase EGL-9. From a genetic screen, we found that the cytochrome P450 oxygenase CYP-13A12 acts in response to the EGL-9–HIF-1 pathway to facilitate the O2-ON response.
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  • Simulation of Physicochemical and Pharmacokinetic Properties of Vitamin D3 and Its Natural Derivatives

    Simulation of Physicochemical and Pharmacokinetic Properties of Vitamin D3 and Its Natural Derivatives

    pharmaceuticals Article Simulation of Physicochemical and Pharmacokinetic Properties of Vitamin D3 and Its Natural Derivatives Subrata Deb * , Anthony Allen Reeves and Suki Lafortune Department of Pharmaceutical Sciences, College of Pharmacy, Larkin University, Miami, FL 33169, USA; [email protected] (A.A.R.); [email protected] (S.L.) * Correspondence: [email protected] or [email protected]; Tel.: +1-224-310-7870 or +1-305-760-7479 Received: 9 June 2020; Accepted: 20 July 2020; Published: 23 July 2020 Abstract: Vitamin D3 is an endogenous fat-soluble secosteroid, either biosynthesized in human skin or absorbed from diet and health supplements. Multiple hydroxylation reactions in several tissues including liver and small intestine produce different forms of vitamin D3. Low serum vitamin D levels is a global problem which may origin from differential absorption following supplementation. The objective of the present study was to estimate the physicochemical properties, metabolism, transport and pharmacokinetic behavior of vitamin D3 derivatives following oral ingestion. GastroPlus software, which is an in silico mechanistically-constructed simulation tool, was used to simulate the physicochemical and pharmacokinetic behavior for twelve vitamin D3 derivatives. The Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) Predictor and PKPlus modules were employed to derive the relevant parameters from the structural features of the compounds. The majority of the vitamin D3 derivatives are lipophilic (log P values > 5) with poor water solubility which are reflected in the poor predicted bioavailability. The fraction absorbed values for the vitamin D3 derivatives were low except for calcitroic acid, 1,23S,25-trihydroxy-24-oxo-vitamin D3, and (23S,25R)-1,25-dihydroxyvitamin D3-26,23-lactone each being greater than 90% fraction absorbed.