* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Lecture 02 - Natural products & biosynthesis, web
Survey
Document related concepts
Butyric acid wikipedia , lookup
Citric acid cycle wikipedia , lookup
Plant nutrition wikipedia , lookup
Fatty acid metabolism wikipedia , lookup
Fatty acid synthesis wikipedia , lookup
Proteolysis wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Peptide synthesis wikipedia , lookup
Genetic code wikipedia , lookup
Ribosomally synthesized and post-translationally modified peptides wikipedia , lookup
Specialized pro-resolving mediators wikipedia , lookup
Drug discovery wikipedia , lookup
Biochemistry wikipedia , lookup
Transcript
Bratton, Heather Bautista, Candie Bui, Steven Chen, John Chem 444 Biol 444 Chan, Hiu Fai Chida, Odette Doan, Chad Cueva, Carla Ho, Joyce Golanbar, Gelareh Karimbabai Massihi, Anna Kashiwabara, Claudine Krasner, Danielle Kopilec, Jaimisyn Loi, William Lau, Jensen Malette, Jacqueline Le, Giang-Tuong Nguyen, Trang Lee, Margaret Robles, Marisa Mata, Francisca Tallorin, Lorillee Nguyen, Thuy Nhi Truong, Daniel C Phillips, Irving Udeh, Francis Romero, Marcelo Villalvazo, Adrianne Wang, Tony Yeh, Enrenn Wittig, Michelle Primary (1°) Metabolism - Construct common biological macromolecules from simple building blocks found within every cell - Typically a process of polymerization, stringing monomers together into a macromolecule that performs a cellular function sugars polysaccharides amino acids proteins fats phospholipid bilayers - Block production: cell dies (primary metabolites are essential) Secondary (2°) Metabolism - Synthesize compounds that are unique to a particular species or genus (unlike common proteins, lipids, etc.) - Molecules may have extremely complex structures - These molecules typically have no effect on the producing organism, but are often highly biologically active against other organisms (competitors, pathogens, predators) - Often present at extraordinary concentrations, >10% of the dry weight of the organism inference is, they must do something Natural Products: Folk to Modern Medicines - Humans have long used chemicals in plant and animal extracts for many purposes: medicines, poisons, recreational stimulants - Since the 1800’s, chemists have characterized and synthesized such natural products, uncovering the basis for folk remedies - Identifying the mechanism of action of natural products was the genesis of modern drug discovery - The active ingredients in many ancient curatives are still used medicinally today Natural Products 1: Toxins Rotenone - Natural fish + insect poison Curare (Tubocurarine chloride) - Derived from 2 South American plant genera - Used as arrow-tip poison by native peoples - Blocks transmission of acetylcholine signal to muscles, causing instant paralysis - 1st drug used as muscle relaxant in surgery Natural Products 1: Toxins Hyoscine (= scopolamine) - Derived from plants: deadly nightshade (belladonna), mandrake - In ancient Greece, mandrake was used as an anaesthetic (or poison, in higher doses) - “Witches” smeared extracts on their armpits: avoided toxic oral route, got maximum hallucinogenic effect = felt like they were flying - Blocks certain acetylcholine receptors - Modern use: prevention of motion sickness (patches behind the ear) Natural Products 2: Medicines COCH3 Salicin Acetyl-salicilic acid: aspirin - From Willow tree bark, which was used in folk remedies for treating fevers - Led to synthetic analogue, modern aspirin Natural Products 2: Medicines Ventolin Ephedrine - From Ephedra plants, basis of ancient Chinese herbal remedy “Ma Huang” (100 AD) for treating respiratory illness - Used clinically since 1926 as bronchodilator to treat asthma - Similar to adrenaline, but also stimulates heart (not good in a drug) - Stimulated research resulting in the non-stimulant drug Ventolin Natural Products 2: Medicines Quinine - Found exclusively in the bark of the Chinona tree - Used as a malaria treatment since 1600’s - Now synthetic derivatives used, due to widespread resistance Natural Products 3: Stimulants Caffeine Nicotine - Caffeine-containing plant leaves + seeds have long been brewed to produce stimulant drinks - Such stimulants naturally act as feeding deterrents to repel insect herbivores that consume plants leaves - Tobacco plant can up its production of nicotine 4-fold when under attack by insects; nicotine by-products are used as insecticides Natural Products 3: Stimulants Cocaine - Coca leaves have been used as a source of cocaine for > 2,000 yrs - Used by Incas in religious ceremonies - Introduced to Europe by conquistadores - Leaves chewed daily by >8 million native peoples in the Andes, to alleviate feelings of hunger and fatigue - Inhibits re-uptake of excitatory neurotransmitter dopamine Natural Products 4: Halucinogens Morphine (= opium) Heroin (synthetic derivative) - Found in only 2 species of poppy flower (Papaver) - Milky exudate of seed capsules is 25% opiate - Used as a baby calming treatment in ancient Egypt - Binds to brain receptors for short peptides called enkephalins, derived from endorphins Natural Products 4: Halucinogens Similar spatial relationships of (*)-marked atoms responsible for similar pharmacological effects Enkephalin Morphine * * * * Natural Products 4: Halucinogens Tetrahydrocannabinol Lysergic acid - Lysergic acid is the parent compound from which ergot alkaloids are derived, such as LSD Lysergic acid Diethylamine (LSD, synthetic) - Produced by fungus; often affected stored grain in Middle Ages - Such compounds found in Aztec “magical” preparation ololuiqui - Structural mimics of human neurotransmitter 5-hydroxytryptamine Secondary Metabolites - Produced from a small number of key intermediates, often generated as by-products of primary metabolism acetate (in the form of acetyl coA) mevalonate 4-carbon sugars - Perhaps arose as a means of dealing with excess metabolic intermediary compounds -2o metabolites then took on ecological roles as toxins, etc. Secondary Metabolites - Typically play ecological roles in nature, deterring would-be pests, predators or pathogens - Affect humans due to structural resemblance to innate neurotransmitters, or by binding to proteins in a way that disrupts normal cellular function - Natural products are the basis for a big % of pharmaceutical drugs currently on the market - Simple building blocks serve as the basis for each major pathway of secondary metabolism: (1) Shikimate Aromatics (ring - C3 chain) (2) Amino acids Alkaloids, Penicillins (N-containing) (3) Mevalonate Terpenes, Steroids (4) Acetate Polyketides (aromatics, macrocycles) (photosynthesis) Polysaccharides Glycosides Nucleic Acids phosphoenol pyruvate Shikimate pathway Aromatic Compounds Lignans Shikimate pyruvate acetyl CoA CH3COSCoA aromatic amino acids aliphatic amino acids CITRIC ACID CYCLE (1) Alkaloids (2) Peptides Penicillins Cyclic Peptides CH3COSCoA -O 2CCH2COSCoA CH3COCH2COSCoA CH3COSCoA CH3COSCoA mevalonate Polyketides, Fatty Acids Isoprenoids (terpenes, steroids, (3) carotenoids) (4) Prostaglandins, Macrocyclic Antibiotics (1) Shikimate pathway from the Japanese flower shikimi (シキミ, Illicium anisatum) (A) Biosynthesis of aromatic amino acids (tyrosine, phenylalanine, and tryptophan) lead to alkaloids (B) Build aromatic secondary metabolites Shikimate Podophyllotoxin Shikimate biosynthesis Shikimate + PEP Chorismate Prephenate Other shikimate metabolites: ring-C3 ...ring-C2 ...ring-C1 + NH3 Cinnamic acid - NH3 Tyrosine, Phenylalanine Biosynthesis of phenyl compounds ring-C1 type vanillin vanillic acid salicin salicylic acid - In plants, many shikimate metabolites are allelopathic: they inhibit growth of competitors - Insoluble forms often linked to sugars in plant tissue - Soluble acidic forms leach out into surrounding soil in rain phenylalanine Lignans & Lignins Cinnamic acid Polymerization: complex lignins Enzymatic coupling: dimeric lignans Cinnamyl alcohol Podophyllotoxin Large % of woody plant biomass Podophyllotoxin - An important shikimate compound - Used by native Americans to cure warts - Powerful inhibitor of mitosis; found to block enzyme tubulin polymerase - - Flavanoid Biosynthesis Shikimate + 3 acetates = flavanones Cause bitter tastes in plants, especially polymerized tannins; deter feeding by herbivores Derived compounds are responsible for much of plant color (2) Alkaloids (2) Amino acids Alkaloids, Peptides, Penicillins Penicillin Strychnine (alkaloid) Cyclosporin A (cyclic peptide) Alkaloid characteristics - Non-(normal)-peptide, non-nucleic acid compounds that contain nitrogen - Common in fungi, plants, insects + amphibians - Derived from amino acid precursors Tyramine Tyrosine Dopamine Mescaline - potent hallucinogen from the peyote cactus - competitively binds to dopamine receptors Penicillin Biosynthesis a-adipate + cysteine + valine - start with peptide made of 3 amino acids (including a non-standard a.a., a-adipate) a-adipate + cysteine + valine isopenicillin synthase penicillin N epimerase isopenicillin N cephalosporins penicillins Penicillins: Mechanism of Action This class of antibiotics interferes with synthesis of the cell wall of Gram-positive bacteria (Staphylococci, Streptococci) Cell wall is a repeating polymer of disaccharide, tetrapeptide repeats cross-linked into a 3D matrix (1) cleave here (transpeptidase) sugar - sugar - phospholipid L-ala — D-glu — L-lys — D-ala — D-ala (glycine)5 (2) cross-link here Penicillins: Mechanism of Action Penicillins inhibit the bacterial transpeptidase enzyme by mimicking its natural substrate, the terminal D-ala—D-ala Transpeptidase attacks the b-lactam ring of penicillin, forms a covalent bond; enzyme is now out of business (1) NO CLASS next Monday (2) For NEXT WEDNESDAY – - bring to class a small amount of some spice, seeds, leaves, fruit, or medicinal herb - pick something with a strong taste/smell, or that you know is used in a folk remedy - at Wednesday’s lecture, you will put your material in a tube and label it; I will then add solvent and extract the natural products from it over the weekend - in the next lab, you will bioassay the extracts of your material for antibiotic activity and cytotoxicity