Introduction to Bioorganic Chemistry and Chemical Biology Answers to Chapter 9 (in-text & asterisked problems) Answer 9.1 Names and acronyms from August 2011 issues of chemistry/biology journals are listed below. The important point is that most of the papers in the current research literature involve mysterious acronyms. The goal of this chapter is to familiarize you with those acronyms that relate to signal transduction pathways that affect gene transcription in humans. Journal of Biological Chemistry 286, Issue 34 (2011) Smad2/3 (a hybrid of C. elegans Sma (small) gene and Drosophila Mad (Mothers against dpp) gene) Hepatocyte Nuclear Factor 4α RNA Photosystem II (PSII)–Psb27 (photosystem protein b27) protein complex ATP synthase dentin matrix protein integrin MSH2 (DNA repair proteins homologous to yeast mutS/hexA) Cdt2 (protein target of target of Cdc10 transcriptional regulation) P21Waf1/Cip1 (kinase inhibitor protein 21 encoded by the Waf1/Cip1 genes) VAMP8 (Vesicle-associated Membrane Protein 8) SNARE (Soluble N-Ethylmaleimide-sensitive Factor Attachment Protein Receptor) GSK3β (Glycogen Synthase Kinase-3β) PTTG1/Human Securin (protein from Pituitary Tumor-Transforming Gene 1) Myocyte Enhancer Factor 2C, an Osteoblast Transcription Factor aurora-A augmin Hice1 Protein (Hec1-interacting and centrosome-associated 1) microtubule ARD1 (Arabidopsis Acireductone Dioxygenase 1) Heterotrimeric G protein β subunit Hsp90 (Heat-shock protein 90) Immunophilin FKBP51 (FK-506 binding protein 51) PSKs/TAOKs (Prostate-derived Sterile 20-like Kinases) glucocorticoid Dig2/RTP801/REDD1 (dexamethasone-induced Gene 2 Protein) NKCC2 (bumetanide-sensitive Na+,K+,2Cl– Cotransporter) Tamm–Horsfall protein CaV1.3 channels (voltage-gated calcium channel 1.3) c-Jun kinase (the Jun oncogene from Avian sarcoma virus was named after Ju nana, the Japanese word for 17) Runx2 protein (Runt-related transcription factor 2) Escherichia coli DinD protein (DNA damage inducible protein D) RecA (DNA recombinase A) VAP-1 (Vascular Adhesion Protein-1) oxime acetylcholinesterase 1 2 Introduction to Bioorganic Chemistry and Chemical Biology: Answers to Chapter 9 cytochrome P450SPα (a heme enzyme that absorbs light at 450 nm) fatty acid autotaxin Egr-1 protein (Early Growth Response 1) HNF4α (Hepatocyte Nuclear Factor 4α) SHP (Small Heterodimer Partner) Mef2A transcription factor (myocyte enhancer factor 2A) GRTH/DDX25 (Gonadotropin-regulated Testicular RNA Helicase) StAR (Steroidogenic Acute Regulatory protein) androgen receptor TGF-β1 (Transforming Growth Factor-β1) microRNA 143/145 TLR4 protein (Toll-like receptor 4) MMP-1 (Matrix Metalloproteinase-1) Chemical Biology 50, Issue 8 (2011) retinal mitochondrial Lon protease docataxel tubulin Hsp90 (heat shock protein 90) JNK (Jun kinase) Sab kinase (SH3 domain-binding protein that preferentially associates with Btk) mycobacterial arabinosyltransferase decaprenylphosphorylarabinose analogues Kalata B1 Kir2 inward rectifier potassium channels (inwardly rectifying potassium channel 2) RNA Biochemistry 50, Issue 33 (2011) p53 (mammalian tumor suppressor protein (53 kDa)) group 3 LEA protein (Late Embryogenesis Abundant) nucleoplasmin histone prion P. aeruginosa type III secretion translocators P. aeruginosa heteromeric transmembrane pores tyrosyl tRNA synthetase nitric oxide synthase Hsp70 (heat shock protein 70) thioredoxin rhodopsin phoborhodopsin prolyl–acyl carrier protein oxidase P. aeruginosa isochorismate–pyruvate lyase GTPase chloroplast signal recognition particle S100A4 (calcium-binding proteins soluble in 100% saturated ammonium sulfate) myosin-IIA mouse olfactory receptor glmS riboswitch (glucosamine-6-phosphate activated ribozyme) glucosamine 6-phosphate α-anomer DNA polymerase RNA frataxin cyclotide GluA2 AMPA receptor (A2 ion channel receptor that binds to glutamate) Introduction to Bioorganic Chemistry and Chemical Biology: Answers to Chapter 9 Science 333, August 11 (2011) Fcγ receptor (receptor that binds to immunoglobulin constant fragment γ) agonistic CD40 antibodies (complementarity determining/determinant 40) Nature 476, Number 7360 (2011) Lgr5 homologues (leucine-rich repeat-containing G protein-coupled receptor 5) Wnt receptors (Wnt is a hybrid of the Drosophila Wingless gene and the mammalian integration 1 gene) R-spondin histone 14-3-3 proteins rice Hd3a florigen (heading date 3a) MCU (mitochondrial calcium uniporter) ribosome Answer 9.2 Cycloheximide would have no effect since mucin release does not involve protein synthesis. Physostigmine would enhance the effect of acetylcholine by preventing hydrolysis by acetylcholinesterase. Atropine would inhibit the rapid release of mucin by antagonizing the effect of acetylcholine. Answer 9.3 Nuclear receptors and gas receptors. Answer 9.4 The androgen receptor (AR) binds duplex DNA with the sequence AGGTCA; the estrogen receptor (ER) binds to duplex DNA with the sequence TGTTCT. By connecting the DNAbinding domain of the androgen receptor to FKBP12 and the DNA-binding domain of the estrogen receptor to mTOR, the two domains will dimerize and bind to DNA in the presence of rapamycin. Semiflexible peptide linkers would be needed to connect the domains; the C termini of FKBP12 and mTOR are closer together than the N termini. 5'-AGGTCANNNTGTTCT-3' 3'-TCCAGTNNNACAAGA-5' AR DBD ER DBD 5'-AGGTCANNNTGTTCT-3' 3'-TCCAGTNNNACAAGA-5' rapamycin AR DBD ER DBD FKBP12 mTOR FKBP12 mTOR Introduction to Bioorganic Chemistry and Chemical Biology | A9145 Van Vranken & Weiss | 978-0-8153-4214-4 Answer 9.5 www.garlandscience.com design by www.blink.biz © The calculations suggest that roughly more than 1% of enone steroids exist as thiol adducts, but Nature is cautious. The equilibrium constant for addition to steroid enones such as testosterone is actually 100-fold less favorable (Keq = 0.02) than it is for 3-methylcyclohexenone. 3 4 Introduction to Bioorganic Chemistry and Chemical Biology: Answers to Chapter 9 1. How much adduct, x, is present at equilibrium? K eq HS + R' R O [A] O R R' [A•R'SH] [R'SH] If thiol is depleted: 10-6 M - x If thiol is not depleted: 10-6 M - x S thiol adduct 0.005 M - x 0.005 M x x 2. Set up equations depending on your assumptions If thiol is depleted: If thiol is not depleted: [A•R'SH] K eq = [A] [R'SH] = (x) (10 -6 M - x)(0.005 M) x = 3. Plug in K eq major prednisone adduct R' O [A•R'SH] [A] [R'SH] = (x) (10 -6 M - x)(0.005 M - x) ... you end up with a quadratic equation; but since [R'SH] >> [A], the answers you calculate, will not be very different from the thiol depletion scenario K eq 1 x K eq 5x10-9 M2 - (0.005 M)• x = x= K eq = (10 -6 M - x)(0.005 M) 5x10-9 M2 1 (0.005 M + ) K eq 5x10-9 M2 - (0.005 M + 10-6 M + O progesterone adduct 1 )•x + x2 = 0 K eq O S O less reactive K eq ~ 7,000 S R' K eq ~ 2 M-1 x = 0.0097x10-6 M thiol adduct 0.990x10-6 M prednisone left over x = 0.0099x10-6 M thiol adduct 0.990x10-6 M progesterone left over 99% of progesterone left over 99% of progesterone left over Answer 9.6 Introduction to Bioorganic Chemistry and Chemical Biology | A9146 Van Vranken & WeissH435W, | 978-0-8153-4214-4 H435F, H435K, and H435R are too big and or © www.garlandscience.com design by www.blink.biz too polar to form complementary interactions with the bulky ethoxy group of QH2. H435G is probably too small and would leave empty space. The H435A mutant is just right to complement the thyroid mimic QH2. Answer 9.7 A IL-3, GM-CSF, IL-6, and IL-5 B IL-3, IL-7, IL-6, and IL-5 Answer 9.8 Most noncovalent interactions between small molecules and proteins have fast on-rates and reach equilibrium very quickly. The fact that inhibition increases with longer incubation times and that the sterically similar analog is inactive suggests a covalent reaction between stattic and STAT3, which has numerous free cysteine residues. Cys712 (PDB 1BG1) makes contact with the active site and could form an adduct with the vinylsulfone moiety. Cys - O 2N Cys S .. S O O S O 2N S O O Introduction to Bioorganic Chemistry and Chemical Biology | A9147 Van Vranken & Weiss | 978-0-8153-4214-4 © www.garlandscience.com design by www.blink.biz Introduction to Bioorganic Chemistry and Chemical Biology: Answers to Chapter 9 Answer 9.9 The extracellular environment favors disulfide formation. A cysteine residue stabilizes the dimeric form of the receptor by forming a cystine disulfide crosslink. R248C or S249C FGFR3 monomers dimer D1 D1 D1 D2 D2 D2 C D2 C C C D3 D1 D3 D3 D3 disulfide bond P P Introduction to Bioorganic Chemistry and Chemical Biology | A9148 Van Vranken & Weiss | 978-0-8153-4214-4 Answer 9.10 © www.garlandscience.com design by www.blink.biz At a PD173074 concentration of 1000 nM, FGFR1, FGFR2, FGFR3, and VEGFR2 would be more than 90% inhibited. Answer 9.11 A FGFR, Shc1, MEK, ERK, and the transcription factor B FGFR3 and Shc1 C FGFR3, Shc1, and ERK (which is activated through the phosphorylation of both threonine and tyrosine in its activation loop) Answer 9.12 H N His H N -HO 3PO -HO 3PO His H N N+ H H O H N DAG O OP H H O O +N H Arg OH N N H salt bridge H H N N+ H -HO 3PO H N H N - H O P O O HO3PO -HO 3PO OH H O - H H H +N N H N H Arg His N+ H His H N His N + H H - ..O HO O O -HO PO P 3 H H +N O O H Arg -HO PO 3 N N OH H H H N O H N N+ H .. DAG HO O O O-HO PO P 3 H H +N O -O H Arg -HO PO 3 N N OH H H His ..N N+ H HO H N N+ H - His N His DAG O OP H H O O +N H Arg OH N N H H 3PO -HO His O: HO His H + DAG HO O O O -HO PO P 3 H H +N O -O H Arg -HO PO 3 N N OH H H H N His N+ H N: HO His N+ H 5 6 Introduction to Bioorganic Chemistry and Chemical Biology: Answers to Chapter 9 H N His H N -HO H O -HO H N H O OP H H O O +N H Arg OH N N H H 3PO 3PO H N His N+ H N: HO His N+ H -HO H N H O OP H H O O +N H Arg OH N N H H HO3PO 3PO H N His N+ H .. O HO - His N+ H N+ H H O OP H H .. +N O -O H Arg N N OH H H HO -HO O 3PO -HO His 3PO Answer 9.13 O O H AcO MeO H O AcO MeO O O O + H AcO MeO .. H2N R O AcO MeO H A O H O + H O :N R H O O OH : A- N H + R or... O H etc. AcO MeO H O O O AcO MeO + OH O + N R H : AH H O O H O O O AcO MeO O H AcO MeO H O H O O O an equally acceptable mechanism would involve... O O H O O O H A O O O etc. O O O + OH H AcO MeO O O :Nu H A O: + :Nu O Introduction to Bioorganic Chemistry and Chemical Biology | A9150 Van Vranken & Weiss | 978-0-8153-4214-4 Answer 9.14 www.garlandscience.com design by www.blink.biz © AlF3 can form a non-hydrolyzable adduct with GDP that mimics GTP. O O F Al FF - OO O O P P :O O O N O HO N OH NH N NH2 F - O O OF O Al P P F - O O O non-hydrolyzable Introduction to Bioorganic Chemistry and Chemical Biology | A9151 Answer 9.15 Van Vranken & Weiss | 978-0-8153-4214-4 N O HO N NH N NH2 OH design byadenylyl www.blink.biz © www.garlandscience.com Because forskolin activates cyclase and a CB1 agonist reverses the effect of forskolin, it suggests that CB1 is coupled to Gαi, an inhibitor of adenylyl cyclase. If the CB1 receptor is coupled to Gαi, the effect of Δ9-tetrahydrocannabinol would be inhibited by pertussis toxin. Introduction to Bioorganic Chemistry and Chemical Biology: Answers to Chapter 9 Answer 9.16 Various authors have suggested that aldehydes bind to the I7 odorant receptor as an iminium ion (also known as a Schiff base), but there is no mechanistic evidence for or against the hypothesis. helix 4 K164 Y107 HO helix 3 +HN O HO O - D204 Y264 helix 5 helix 6 F205 F262 Introduction to Bioorganic Chemistry and Chemical Biology | A9152 Van Vranken & Weiss | 978-0-8153-4214-4 Answer 9.17 © www.garlandscience.com design by www.blink.biz + : + + : + + : + - .. - .. - .. Introduction to Bioorganic Chemistry and Chemical Biology | A9153 Van Vranken9.18 & Weiss | 978-0-8153-4214-4 Answer © www.garlandscience.com design by www.blink.biz (From J.T. Gerig et al., J. Inorg. Biochem. 31:113–121, 1987. With permission from Elsevier.) CO2N O OH O N O OH O O Ca O O O N O O Introduction to Bioorganic Chemistry and Chemical Biology | A9154 Answer 9.19 Van Vranken & Weiss | 978-0-8153-4214-4 www.garlandscience.com design by www.blink.biz of oligonucleotides in Chapter 3. This is similar to the photodeprotection © H -O O N + O- H 2C -O hν RO O N O: N + O- 2C O N OH -O2C O R' -A: -O2C H O N O+ H OO -O2C .. N+ RO RO H A -O2C RO O :O N -A: -O2C RO OH OH + O N -O2C O O .. R' H A O O-O2C .. N+ H O+O N -O2C .. H2O O+ H O N O- O N -O2C HO OH 7 O N O: H A O N -O2C RO 8 OH :O N -O2C O OH OH + O N -O2C O Introduction to Bioorganic Chemistry and Chemical Biology: Answers to Chapter R' R' O O +9 .. -A: -O2C or... H O H H A O O-O2C .. N+ ON + RO O N -O2C HO -O2C .. H2O O N O- -O2C RO RO Introduction to Bioorganic Chemistry and Chemical Biology | A9155 Answer Van Vranken &9.20 Weiss | 978-0-8153-4214-4 design by www.blink.biz © www.garlandscience.com The product is undoubtedly a conjugate addition product. The stereochemistry at the newly formed stereogenic center α to the carbonyl cannot be readily predicted without knowledge of the interaction between kamebakaurin and the binding site. O OH HO :S HO O OH Cys HO H S HO Cys OH OH Introduction to Bioorganic Chemistry and Chemical Biology | A9156 Van Vranken & Weiss | 978-0-8153-4214-4 *Answer 9.23 © www.garlandscience.com design by www.blink.biz A Tyrphostin would inhibit all elements of these pathways. B Wortmannin inhibits PI3K, the first enzyme in the apoptotic pathway. C Rapamycin would selectively inhibit TOR and the effects on protein synthesis. *Answer 9.25 R R hν H H hν H H HO HO photopyrocalciferol R R >100°C H pyrocalciferol H H H HO HO precalciferol calciferol Introduction to Bioorganic Chemistry and Chemical Biology | A9159 Van Vranken & Weiss | 978-0-8153-4214-4 *Answer 9.27 design by www.blink.biz © www.garlandscience.com The residues that contribute most significantly to binding are positively charged lysines and arginines. It is therefore probably interacting with negatively charged aspartate or glutamate residues on the receptor. *Answer 9.29 There is some ambiguity in the P + 3 position, but on the basis of the intensity of the spots, the best consensus sequence would be * XXPXYVNIR The authors were cautious in their interpretation of preferences and counted only spots that bound strongly to Grb2. * I XXXXYI V NLX V *Answer 9.31 The simple way to do this is to load a suitably protected lysine onto an acid-labile resin and then deprotect both the α-amino group and the side chain. Then one can perform traditional solid-phase peptide synthesis using twice the normal amount of Fmocprotected amino acids. Finally the peptide can be cleaved under mild acid conditions. acid cleavage: e.g., (Arg protected by Pbf or Pmc) O H2N O O NH2 O H2N O H2N here grow O NH2 NH 2 grow here grow here O H2N O NH2 grow here 1:1 O acid cleavage: e.g., CF 3CO2H/ (Arg protected by Pbf or Pmc) H SPPS to Bioorganic(Arg cleavage: e.g., protected by Pbf or Pmc) Biology:acid Introduction Chemistry and Chemical Answers CH 1:1 2Cl2 to Chapter 9 N 1:1H/ O O CF 3CO 2 H SPPS O CO2H/ CF 3Cl NH CH H 2 2 N SPPS -VPPPVPPRRR X H N X CH 2 H2N-VPPPVPPRRR Oacid2Cl2 N acid cleavage: e.g., H2N-VPPPVPPRRR O (Arg protected by Pbf or Pmc) labile NH 1:1 X H2N-VPPPVPPRRR NH acidX H2N-VPPPVPPRRR X 3CO2H/ X O CF acidlabile H SPPS CH2Cl2 labile N H2N-VPPPVPPRRR O NH H2N-VPPPVPPRRR X acidH2N-VPPPVPPRRR X 9 labile The key challenge is how to deprotect the Nα and Nε amino groups without cleaving the amino acid from the resin. The authors attached Nα-Fmoc-Nε-Fmoc lysine to a commercial Wang resin through a carbodiimide coupling and then removed the Fmoc Wang linker groups using piperidine/DMF. O O HMB resin FmocHN H2N O O Wang linker HMB H resin Wang linker O HMB resin N NH piperidine H2N FmocHN O OacidFmocHN Fmoc H2N H O O NH labile DMF NH piperidine Fmoc O N NH acidpiperidine Wangacidlinker Fmoc OHMB resin O O labile DMF O labile DMF FmocHN H2N O H N NH piperidine Fmoc O acidO labile DMF O O NH2 O O O NH2 NH2 O SPPS SPPS H O NH O N O O O O NH2 SPPS H N O SPPS H N O O Alternatively one could attach the first amino acid to acid-labile chlorotrityl resin and follow the same sequence of steps as with the Wang resin. Grb2 peptidimer ligand H Grb2 peptidimer ligand CO2N C-SH3 N-SH3 C-SH3 C-SH3 N-SH3 N-SH3 C-SH3 N-SH3 Grb2 peptidimer ligand H2N-VPPPVPPRRR H NH NHCO2CO2NH Grb2 peptidimer ligand H2N-VPPPVPPRRR NH H2N-VPPPVPPRRR H N CO2H2N-VPPPVPPRRR NH H2N-VPPPVPPRRR H2N-VPPPVPPRRR H2N-VPPPVPPRRR N H2N-VPPPVPPRRR The least desirable solution (that would still work) would be to attach the very common Nα-Fmoc-Nε-Boc lysine to an acid-stable resin such as Merrifield resin and then use TFA to cleave the Boc side chain without cleaving the benzyl ester linkage. very acid-labile H H O O NH N O O very acid-labile O O H N O Merrifield resin i) CF3 CO2 H H2N (remove Boc) Merrifield resin O O Merrifield resin i) CF3 CO2 H O NH H2N CF3 CO 2H ii) i)piperidine Fmoc (remove Boc) O not H2N (remove Boc) O DMF very NH (remove Fmoc) ii) piperidine acid-labile Fmoc NH not ii) piperidine Fmoc O Merrifield notresin DMF very i) CF DMF 3 CO 2 H Fmoc) very (remove acid-labile H2N (remove Boc) Fmoc) (remove O acid-labile veryOacid-labile N very acid-labile Introduction Chemistry and Chemical Biology | A9162 O to BioorganicNH ii) piperidine Van Vranken & WeissFmoc | 978-0-8153-4214-4 not byvery www.blink.biz DMF| A9162 © www.garlandscience.com Introduction to Bioorganic design Chemistry and Chemical Biology to Bioorganic Chemistry and Chemical Biology | A9162 (remove Fmoc) VanIntroduction Vranken & Weiss | 978-0-8153-4214-4 acid-labile Van Vranken & Weiss | 978-0-8153-4214-4 design by www.blink.biz © www.garlandscience.com © www.garlandscience.com design by www.blink.biz Introduction to Bioorganic Chemistry and Chemical Biology | A9162 Van Vranken & Weiss | 978-0-8153-4214-4 © www.garlandscience.com design by www.blink.biz O O O NH2 O O O NH2 NH2 O O NH2 anhydrous HF anhydrous SPPS anhydrous HF SPPS HF SPPS SPPS anhydrous HF 10 Introduction to Bioorganic Chemistry and Chemical Biology: Answers to Chapter 9 *Answer 9.33 high energy excited state OMe hν OO CO2+H O+H aromatic OMe 3N ..N N .. O .. O - O +H3N 2C -O O N JAK OH O O N H O OOH S OH S O SH JAK JAK Introduction to Bioorganic Chemistry and Chemical Biology | A9166 Van Vranken & Weiss | 978-0-8153-4214-4 *Answer 9.37 www.garlandscience.com design by www.blink.biz © NH2 O -O P OO O H N R N R' H H O .. BNH2 O R O -O P OO O H .. N R N R' H O - N .. H H B H N N H R O N H H N R' O NH2 ~ ~ S O R' R NH2 S H N :S O R' O R O N H H N R' O lysine Introduction to Bioorganic Chemistry and Chemical Biology | A9168 Van Vranken & Weiss | 978-0-8153-4214-4 *Answer 9.39 www.garlandscience.com design by www.blink.biz © Me Me HO Me Me synthetic vitamin D2 (ergocalciferol) OH OH liver enzyme; kidney enzyme HO Introduction to Bioorganic Chemistry and Chemical Biology | A9170 Van Vranken & Weiss | 978-0-8153-4214-4 © www.garlandscience.com design by www.blink.biz N+ NO2 free glutamate O SH O O O OMe Introduction to Bioorganic Chemistry and Chemical Biology | A9164 Van Vranken & Weiss | 978-0-8153-4214-4 www.garlandscience.com design by www.blink.biz *Answer 9.35 © JAK O NO2 O- 2C N 2C OMe N+ H N .. O B H +H3N -O H H B: NO2 :OCO2- 3N OMe N -O +H NO2 N+ O- O NO2 H H +N .. N+ O O- O CO2- OMe B: NO2 +N 3N +H3N OMe NO2 .. N N * OMe NO2 ligand for the vitamin D receptor N O O-