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Home , Moxifloxacin, Nalidixic acid, Novobiocin, Prontosil, Quinolone antibiotic, Sahachiro Hata

Mechanistic Classes of Antibacterials Benjamin D. Horning Group Meeting November 30, 2011

http://images.agoramedia.com/cs/eh/cs_diarrhea_antibiotics_causing_diarrhea_article.jpg http://www.irishhealth.com/content/image/853/Image1.jpg Walsh, C. T. : Actions, Origins, Resistance, American Society for Microbiology Press, Washington DC, 2003

Antibacterials- A Subclass of Antibiotics

An is “a chemical substance having the capacity, in dilute solution, to kill or inhibit growth of microorganisms.” This definition includes antifungals and antiprotozoals. Antibiotics travel inside the body to fight microorganisms, are used externally, and are for non-living surfaces.

antibiotics

disinfectants antiseptics antibacterials antifungals antiprotozoals

applied to non- for external applications for internal or kill fungus kill protozoans living objects to living organisms external use (single-celled eukaryotes) http://www.lysol.com/images/products/no-mess-automatic-toiletbowl-cleaner.png, http://www.couponmamacentral.org/wp-content/uploads/2011/09/purell.jpg, http://www.medexpressrx.com/blog/wp-content/uploads/2010/07/antibiotics4.jpg, http://drugster.info/drug/medicament/22969/, http://modernmedicalguide.com/wp-content/uploads/2010/03/Antiprotozoal-.jpg Antibacterials- A Subclass of Antibiotics

in vitro antibacterials human antibacterials veterinary and feedstock antibacterials

S. pyogenes S. pneumoniae S. mutans pyogenes - strep throat, , , necrotizing fasciitis - (bacterial) - , (bacterial) pneumonia - , urinary tract , , (Methicillin-resistant) aureus (MRSA) - Imepetigo, Staph infections,

Image from: http://inst.bact.wisc.edu/inst/images/book_3/chapter_13/13-3.jpg http://www.webcitation.org/5uJyti0mG http://www.medicinenet.com/sepsis/page4.htm

Top-Selling Antibiotics in the USA

O Me Me Me Me Me Me 21 54 N N 94 Me OH N F CO2H H H H H OH OH

N N NH2 NH2 N O OH OH Me Me OH O OH O O OH O OH O O Levaquin (Levofloxacin) Solodyn () Doryx ()

Ortho-McNeil Medicis Medicis $1,355 Million $673 Million $673 Million

O O O 97 125 126 F CO2H F CO2H F CO2H

H H N N N N N N HN HN OMe HN OMe H H Avelox (Moxifloxacin) Ciprodex otic Vigamox (Moxifloxacin) (Cipro and Dexamethasone) Merck Alcon $353 Million Alcon $255 Million $253 Million

HO Me OH Me Me OH 138 O 160 H3N O 166 Me OH N HO O O H H O Cl OH O Me O O O N N H Cl OHMe Me HO O O O NH N Me H O H 2 N N F O H N N N OH N H O H H H NHMe H H OH O OH O O O HO O NH2 O Zyvox () HO OH Oracea (Doxycycline) OH Pfizer Vancocin () ViroPharma Galderma $223 Million $192 Million $187 Million

http://cbc.arizona.edu/njardarson/group/top-pharmaceuticals-poster Antibiotics- Why You Should Care

of 57 million annual deaths

Vaccinations and antibiotics can or prevent the majority of infectious diseases currently afflicting humanity. Antibiotic use introduces evolutionary selection pressure to ; Resistant strains are selected for, and cause antibiotics to become ineffective. Bacterial resistance has been observed for every class of antibiotic introduced, sometimes within one year. New therapies will be needed.

Graph from: Morens, D. M.; Folkers, G. K.; Fauci, A. S. Nature 2004, 430, 242-249 Table from: Palumbi, S. R. Science 2001, 293, 1786-1790

Strategies to Slow the Development of Antibiotic Resistance

108 bacteria 1 bacterium 108 bacteria antibiotic bacterial one error per 107 bases selection for completely resistant treatment growth 10 mutants (~0.3% of genes) resistant bacteria

Overkill (multiple antibiotics) has worked well for HIV/AIDS, but not always applicable for bacteria (side effects).

Direct observation therapy - continue antibiotic until no bacteria remain (not practical).

Use narrow-spectrum antibiotics when applicable.

Withhold the most powerful drugs - prevented vancomycin resistance for >30 years - difficult business model for pharma.

Continue to develop new therapies and improve old therapies.

Palumbi, S. R. Science 2001, 293, 1786-1790 Bacterial Resistance - Three Flavors

Three types of bacterial resistance to antibiotics have been observed, coming either from random under the selection pressure of antibiotics, or from antibiotic-producing NH2 bacteria. Resistance can be spread amongst bacteria via horizontal gene transfer. N N

N N O H N O S Ph Me O N Me O OH O CO2H H2O RlmN Cfr !-lactamase

Ph NH2 N N O NH Me N O S N Me Me O OH HN Me O

CO2H O OH

antibiotic modification export pumps enzymatic target (only natural products (efflux) modification and semisynthetics)

http://www.sciencephoto.com/image/151999/530wm/C0089313-Active_efflux,_artwork-SPL.jpg Fujimori, D. G. et. al. J. Am. Chem. Soc. 2010, 132, 3953-3964

Paul Ehrlich and Discovery

Made seminial contributions in histology, haematology, immunology, oncology, microbiology and pharmacology.

Alongside Ilya Mechnikov, won the Nobel Prize in Physiology or Medicine in 1908 “in recognition of their work on immunity.”

Most famous for his discovery of Salvarsan (, #606), a compound for the treatment of , which was discovered during the first screen of a library of compounds for pharmaceutical activity, and later part of the first optimization of a lead, becoming the first blockbuster drug and presaging modern drug discovery.

OH HO H2N

HO H2N NH2 NH2 and Sahachiro Hata H N As 1910 As 2 As As OH As OH As As As

As As HO NH2 HO NH NH2 NH 2 2 Revised structure of Salvarsan OH

HO NH2 OH Bosch, F.; Rosich, L. Pharmacology 2008, 82, 171-179 www.nobelprize.org/nobel_prizes/medicine/laureates/1908/ Salvarsan http://pubs.acs.org/cen/coverstory/83/8325/8325salvarsan.html

Lloyd, N. C.; Morgan, H. W.; Nicholson, B. K.; Ronimus, R. S. Angew. Chem. Int. Ed. 2005, 44, 941-944 The Four Major Targets of Antibiotics

Walsh, C. T. Nature Reviews Microbiology 2003, 1, 65-70 Walsh, C. T. Antibiotics: Actions, Origins, Resistance, American Society for Microbiology Press, Washington DC, 2003

The Four Major Targets of Antibiotics

Antibiotics either target processes that are unique to bacteria - cell wall biosynthesis and metabolism - or processes that have different enough machinery to allow selective inhibition of bacterial over human versions - protein biosynthesis and DNA and RNA replication and repair.

O O O H NH2 NH2 N Me S S S NH2 O O O O N H2N N H2N

H N - 1936 2 - 1932 O H N O CO2H S Me O N O O N H H H2N N HN N HO2C H

H2N N N H Tetrahydrofolic acid

NH2 OMe N

H2N N OMe OMe - 1940s

Walsh, C. T. Nature Reviews Microbiology 2003, 1, 65-70 Walsh, C. T. Antibiotics: Actions, Origins, Resistance, American Society for Microbiology Press, Washington DC, 2003 Antibacterials Inhibiting Bacterial Folate Biosynthesis

Prontosil was the first sulfa drug, discovered by O while working for AG. NH2 S NH Bayer AG hoped to use its expertise in dyes to 2 O develop a Ehrlich-style “” dye that could N N be selective for , found Prontosil. Immensely successful as the first broad-spectrum H N 2 Prontosil - 1932 antibiotic. Bayer AG’s revenue stream was undercut when a team of French scientists found that Prontosil is a , and becomes sulfanilamide in the body, the patent for which had long ago expired. in vivo Gerhard Domagk metabolism Massive product and marketing of sulfanilamide Nobel Prize 1939 followed; One preparation, called Elixir “for the discovery Sulfanilamide, was a solution in ethylene glycol. of the antibacterial This raspberry-flavored concoction caused over effects of prontosil” O NH2 100 deaths in 1937. S O In 1938, the FDA passed the Federal Food, Drug H2N and Cosmetic Act, requiring safety tests for a variety of product. This is why we do clinical trials Sulfanilamide - 1936 for all new medicines today.

http://www.nobelprize.org/nobel_prizes/medicine/laureates/1939/domagk.html# http://www.fda.gov/AboutFDA/WhatWeDo/History/ProductRegulation/SulfanilamideDisaster/default.htm for a history of clinical trials, see: http://blogs.scientificamerican.com/guest-blog/2011/10/06/molecules-to-medicine-clinical-trials-for-beginners/

Sulfa Drugs - Tetrahydrofolate Biosynthesis in Bacteria

O O O O P P P P O O O OH O O O OH O- O- O- O- N N O H HN HN N CO2H S Me O N H2N N N para-amino H2N N N O H H H2N benzoate H2N

7,8-Dihydropteroate Synthase 7,8-Dihydropteroate Synthase O H N CO2H S O O Me O N O N N HN N HN N H H

H2N N N H2N N N H H 7,8-Dihydropteroate 7,8-Dihydropteroate

O CO2H O CO2H

O N O N H NADPH H H N N HN N HO2C HN N HO2C H H

H2N N N H2N N N H H 7,8-Dihydrofolate 5,6,7,8-Tetrahydrofolate Sulfa Drugs - Tetrahydrofolate Biosynthesis in Bacteria

O O O O O H P P N P P O O O OH S O O O OH O- O- Me O- O- N O N N O H HN HN O N CO2H S H2N Me O N H2N N N para-amino SulfamethoxazoleH2N N N O H H H2N benzoate H2N combination 7,8-Dihydropteroate Synthase marketed as 7,8-Dihydropteroate Synthase co-trimoxazole O H N CO2H NH2 S O O Me OMe George H.O Hitchings N O N N N Nobel Prize 1988 HN N HN N H H “for their discoveries of H2N N OMe important principles for H2N N N H2N N N H OMe H drug treatment” 7,8-Dihydropteroate Trimethoprim 7,8-Dihydropteroate

O CO2H O CO2H

O N O N H NADPH H H N N HN N HO2C HN N HO2C H H

H2N N N H2N N N H H 7,8-Dihydrofolate 5,6,7,8-Tetrahydrofolate

Success and Failure with Bacterial Metabolite Biosynthesis

OH O O Me fatty acid biosynthesis O N H OH OH O CO2H O platensymicin Me O N H H N n HN N HO2C OH H n H2N N N O H Me n

Folate is an essential nutrient for humans, they cannot synthesize it. Bacteria must synthesize folate, and cannot obtain it from their environment.

Zlitni, S. and Brown, E. D. Nature 2009, 458, 39-40 Walsh, C. T. Antibiotics: Actions, Origins, Resistance, American Society for Microbiology Press, Washington DC, 2003 The Four Major Targets of Antibiotics

H N S Ph Me O N Me G O CO2H Me O N H N S S N O N N+ O H2N CO H 2 Cefepime ()

HO OH Me OH H3N O

HO O O O Cl Me O O

Cl OH Me Me HO O O O O H H N N N N N O H H H H N O H H H NHMe H H HO O NH2 O Vancomycin (peptidoglycan) HO OH OH

Antibacterials that Target Cell-Wall Biosynthesis

Images from: http://fernness.com/science-01.html Antibacterials that Target Cell-Wall Biosynthesis

MurG Transglycosylases

MurB

MurC Transpeptidase β-lactams MurD

MurF

Cell wall allows cells to survive in hypotonic media, where otherwise swelling of the cell would cause it to burst. Murein , greek word for wall, enzyme called MurA- G

The cell wall is called murein, from the greek word for wall, and the enzymes involved in its construction are hence named MurA, MurB, etc.

Images from: Höltje, J.-V. Microbiol. Mol. Biol. Rev. 1998, 62, 181-203

β-Lactams: , and

H OH H OH H O O H O H OH Me O O H NHAc HO H O H O H NHAc H Me O O HN O H NHAc O H Me HN O O O HO2C NH O O NH CO2H Me -D-Ala NH O TPase O HO C NH NH 2 2 Me NH

O NH CO2H O NH2 O NH HN Me O -TPase HO2C O R NH O NH Me N H Me O HO2C Me Ph O NH CO2H O O NH H OH N N O NH H Ph S NH Me Me TPase O S H O N Me O O HN Me CO2H Covalent intermediates have half-lives CO H TPase 2 from several hours to many days Walsh, C. T. Antibiotics: Actions, Origins, Resistance, American Society for Microbiology Press, Washington DC, 2003, p. 39 Discovery of Penicillin: Nobel Prize1945

Sir

"for the discovery of penicillin and its curative Sir Howard Florey Dr. Ernst B. Chain effect in various infectious diseases"

assisted by Sir. Robert Robinson http://www.nobelprize.org/nobel_prizes/medicine/laureates/1945/

β-Lactams: Penicillins, Cephalosporins and Carbapenems

H N S S Ph Me O N Me N O R CO2H

Penicillin G thiazolidine (penicillin) Me O N H N S S S N O N N+ N O R H2N CO2H Cefepime dihyrothiazine (cephalosporin)

HO H NH2

Me S N O N CO2H R Thienamycin dihydropyrrole ()

Structural modifications allow decreases susceptibility to β-lactamases. β-Lactams: Resistance Mechanisms - β-Lactamases

Costs of over $30 billion per year due to β-lactamase-mediated resistance

Ph Ph

O NH O NH H N Ph S O S Me O S Me Me !-lactamase H2O H2O O N Me O HN Me OH HN Me O Enz CO2H CO2H CO2H OH inactive Enz

Me S O

O H2N N N H NH N S !-lactamase N S H O S O 2 Me O N O Me N N+ Me HN N+ O slower H N O H O 2 2 Enz CO H CO H OH 2 2 Enz

larger side chain slows hydrolysis by occluding water from the active site

Statistics from: Palumbi, S. R. Science 2001, 293, 1786-1790

β-Lactams: Resistance Mechanisms - β-Lactamase Inhibitors

Clavulanic acid (right) shows minimal activity against transpeptidases HO (penicillin-binding proteins) but is highly active against β-lactamases. O N A combination of Clavulanate and Amoxicillin is marketed by O GlaxoSmithKline as Augmentin (and by Pfizer as Clavamox) CO2H

HO HO HO O O + O !-lactamase O O N O HN O HN H+ O Enz Enz CO2H CO2H CO2H OH Enz

Enz Nuc Enz H Enz O Nuc O Nuc O O O + + O O H2N O HN Enz Enz Enz

CO2H CO2H OH H+ OH

Statistics from: Palumbi, S. R. Science 2001, 293, 1786-1790 : Vancomycin and Teicoplanin

OH OH HO OH O Me Me OH OH H3N O N H O Me HO O O O O Cl Cl O O Me O O OH HO O Cl OH O O Cl Me Me HO O HO O H H O O O Me NH N N O H H N N N O N H HN H O N N N O O O H NH2 H H H N O H H H NHMe HN H H O HO HO HO C O 2 OH NH2 O OH O HO O HO HO OH HO OH OH OH vancomycin teicoplanin

“The antibiotic of last resort” Marketed by Sanofi-Adventis Approved in 2009 Discovered in soil sample from Borneo, isolated by Eli Lilly chemist Edmund Kornfeld >30 years before resistance observed (1953 to 1987)

Chen, L.; Walker, D.; Sun, B.; Hu, Yanan; Walker, S.; Kahne, D. Proc. Nat. Acad. Sci. 2003, 100, 5658-5863

Aminoglycosides: Vancomycin and Teicoplanin Aminoglycosides: Vancomycin Resistance

HO HO OH OH Me Me OH OH H3N O H3N O

HO HO O O O O O Cl O Cl Me O O Me O O

Cl OH Me Me Cl OH Me Me HO O HO O O O O O O O H H H H N N N N N N N N N N O H O H H H H H H H N O H H H NH N O H H H NH H H Me H H Me HO O HO O NH2 NH2 O O HO OH HO OH OH OH

O Me H O O Me O N O R N O R N O H H O Me O Me

Removing this single hydrogen-bond interaction reduces vancomycin affinity for the terminal dipeptide by 1,000-fold. Replacing the terminal D-Ala with D-Ser reduces affinity by 6-fold

Aminoglycosides: Vancomycin Resistance

HO HO OH OH Me Me OH OH H3N O H3N O

HO HO O O O O O Cl O Cl Me O O Me O O

Cl OH Me Me Cl OH Me Me HO O HO O O O O O O O H H H H N N N N N N N N N N O H O H H H H H H H N O H H H NH N N+ H H H NH H H Me H H H H Me HO O HO O NH2 NH2 O O HO OH HO OH OH OH

O Me H O O Me O N O R N O R N O H H O Me O Me

Removing this single hydrogen-bond interaction reduces vancomycin affinity for the terminal dipeptide by 1,000-fold. Replacing the terminal D-Ala with D-Ser reduces affinity by 6-fold Boger, 2011 showed that activity can be returned by replacing the amide with an amidine

Xie, J.; Pierce, J. G.; James, R. C.; Okano, A.; Boger, D. L. J. Am. Chem. Soc. 2011, 133, 13946-13947 The Four Major Targets of Antibiotics

O Me Me

HO OH O Me OH Me NMe2 O HO O N N H Et O O O Me N Me F O O OMe O Me Me O OH Me

Erythromycin Linezolid () (Oxazolidinone)

Me Me OH N H H OH

NH2 OH OH O OH O O

Tetracycline

Antibiotics Blocking Bacterial Protein Biosynthesis

transcription translation

DNA RNA protein

Figure from: Steitz, T. A. Nat. Rev. Mol. Cell Biol. 2008, 9, 242-253 Antibiotics Blocking Protein Biosynthesis:

O O N N Me Me Me Me O Me Me HO OH HO OH O N Me OH Me Me OH Me OH NMe O 2 Me HO N Me Et O O O Me Et O OH NMe2 Me HO Et O O O Me O O OMe O OH O O Me Me Me O OH Me Me Erythronolide Erythromycin Telithromycin (Erythromycin aglycone)

First isolated by Eli Lilly Scientist J. M. McGuire from soil samples collected by A. Aguilar which contained Saccharopolyspora erythraea, a species of actinomycete (major group of antibacterial-producing bacteria)

Acid-instability hampered widespread application of early derivatives; Mono-deglycosylation, C-6 methylation and carbamate introduction aided in newer generations.

First total synthesis: Woodward, R. B. et. al. J. Am. Chem. Soc., 1981, 103, 3210–3213

Erythromycin Binds to the Ribosome Exit Tunnel

Image from: http://www.weizmann.ac.il/sb/faculty_pages/Yonath/10A-1.jpg Figure from: Schlünzen, F. et. al. Nature 2001, 413, 814-821 Antibiotics Blocking Protein Biosynthesis: Erythromycin

dimethylation or adenosine replacement causes resistance - humans have guanosine

Colored lines indicate groups that are <4.4 Å apart

Figure from: Schlünzen, F. et. al. Nature 2001, 413, 814-821

Erythromycin Resistance in Bacteria O O Me O Me O

Me Me Me Me OH OleI OH Me Me Et O OR1 Et O OR2

O O OMe O O OMe

Me Me Me Me O OH O OH Me Me OleB

NMe2 HO R1= O O Me

HO R2= HO O O O HO NMe2 Me O Me O OH O O O Me

Me Me Me Me OH OleR OH Me Me Et O OR1 Et O OR2

O O OMe O O OMe

Me Me Me Me O OH O OH Me Me Adapted from: Quiros, L. M. et. al. Mol. Microbiol. 1998, 28, 1177-1185 Antibiotics Blocking Protein Biosynthesis: Linezolid (Zyvox)

O

O O N N H N Me F O Linzeolild (Zyvox)

Pfizer, $223 million in 2010

Antibacterial effects of oxazolidinone originally discovered by DuPont, abandoned due to toxicity issues. Pharmacia/Upjohn later salvaged the product and (after being incorporated by Pfizer) released Zyvox in 2000.

To date, Zyvox is the only oxazolidinone clinically approved, but many others are currently in clinical trials

Represents the first widely-used novel antibiotic structural class since the 1960s (fluoroquinolones)

Differences in binding site between other protein biosynthesis inhibitors prevents cross-resistance Structure from: Ippolito, J. A. et. al. J. Med. Chem. 2008, 50, 3353-3356

Antibiotics Blocking Protein Biosynthesis:

O

O O N N H N Me F O

O Me Me

HO OH Me OH Me NMe2 HO and Et O O O Me oxazolidinones interact with the 50S ribosomal O O OMe subunit Me Me O OH Me

Me Me OH N H H interact OH with the 30S

ribosomal subunit NH2 OH OH O OH O O

Figure from: Williamson, J. R. Nature 2000, 407, 306-307 Antibiotics Blocking Protein Biosynthesis: Tetracycline

Me Me Me Me Me Me Cl HO Me N HO Me OH N OH N H H H H H H OH OH OH

NH2 NH2 NH2 OH OH OH OH O OH O O OH O OH O O OH O OH O O

chlorotetracycline tetracycline (aureomycin) (terramycin) (acromycin)

Chlorotetracycline (aureomycin) was the first tetracycline antibiotic, discovered in a soil sample in 1948 (again biosynthesized by actinomycetes) Oxyotetracycline (terramycin) was subsequently discovered in 1949 by a nascent Pfizer, and was the subject of the first mass-marketing drug campaign. This drug put Pfizer on the map. R. B. Woodward and Pfizer collaborated to solve the structure of terramycin, mostly succeeding (mis-assigned one stereocenter)

Hydrogenation of aureomycin gave the deschloro product, which maintained activity, and was one of the first semi-synthetic antibiotics.

Baran group meeting on Tetracyclines (http://www.scripps.edu/chem/baran/html/meetingschedule.html) Chopra, I.; Roberts, M. Microbiol. Mol. Biol. Rev. 2001, 65, 232-260

Novel Tetracyclines from Tetraphase

Me Me F N H H OH O

N NH2 N H OH OH O OH O O

TP-434 Andrew G. Myers Profssor of Chemistry Harvard University

Fully synthetic tetracyclines overcome bacterial resistance problems in ways that semisynthetics are unable to.

Business plan includes developing new broad spectrum antibiotics as well as narrow-spectrum inhibitors.

http://tphase.com/ Antibiotics Interfering with DNA Replication and Transcription

OH OH H N

O Me Me O O

Me O Me Me HO O OH

H2N O

O O

CO2H F CO2H

Me N N N N HN Me Ciprofloxacin O O

F CO2H F CO2H

H N N N N HN N O OMe Me Me H Levofloxacin Moxifloxacin

Fluoroquinolones Affecting DNA Replication and Transcription

O

CO2H Nalidixic acid was the first synthetic , formed as a Me N N byproduct during (anti-malarial) manufacture in the early 1960s.

Me Nalidixic acid

O F CO H Ciprofloxacin, or Cipro, is a second-generation fluoroquinolone, patented in 2 1983 by Bayer A. G. and receiving FDA approval in 1987. substitution at the 6-position (common by this point) provides activity against both gram- N N negative as well as gram-positive bacteria. Sales were $242 million in 2008. HN

Ciprofloxacin

O O Levofloxacin (Levaquin or Tavanic) and F CO H F CO H 2 2 Moxifloxacin (Avelox or Avelon) are fourth- H generation fluoroquinolones, generating $1,355 N N N N HN and $353 million in revenues in 2010, N O OMe respectively. Me Me H Levofloxacin Moxifloxacin Emmerson, A. M.; Jones, A. M. J. Antimicrob. Chemother. 2003, 51, Suppl. S1, 13-20 DNA Replication and Repair Causes Supercoiling

www.benthamscience.com/cmcaca/sample/cmcaca1-1/holden/f3-p7holden.gif open.jorum.ac.uk/xmlui/bitstream/handle/123456789/956/Items/S377_1_013i.jpg

Quinolones Stabilize the DNA-Gyrase Covalent Intermediate

Quinolones (and coumarins) cause accumulation of the doubly-cut covalent DNA-gyrase intermediate. The nature of the binding is uncertain (resistance hotspots on gyrA and parC subunits, may bind altered conformation of DNA)

Tyr122 Tyr122

O OH O P OH O O-

5' A T C G A T C G A T C G A T C G 3' 5' A T C G A T C G A T C G A T C G 3' 3' T A G C T A G C T A G C T A G C 5' 3' T A G C T A G C T A G C T A G C 5' -O O OH P O O HO O F CO2H

Tyr122 R N Tyr122 R R

Pan, X.-S.; Fisher, L. M. J. Antimicrob. Agents Chemother. 1997, 41 (2), 471-474 Walsh, C. T. Antibiotics: Actions, Origins, Resistance, American Society for Microbiology Press, Washington DC, 2003 pp. 71-77 Future Directions of Antibiotics Research - Molecules

Synthetic (top) and natural-product derived (left) antibiotics that have been launched since 2000

PA-824 is a antibiotic, the process- scale synthesis of which was developed at Princeton University

Marsini, M. A.; Reider, P. J.; Sorensen, E. J. J. Org. Chem. 2010, 75, 7479-7482; Butler, M. S.; Cooper, M. A. The Journal of Antibiotics 2011, 64, 413-425

Future Directions of Antibiotics Research - Molecules

Molecules currently in phase III clinical trials

Butler, M. S.; Cooper, M. A. The Journal of Antibiotics 2011, 64, 413-425 Future Directions of Antibiotics Research - Targets

Fatty acid biosynthesis - works well for antiseptics, Two-component signal transduction - unique unlikely to be applicable for antibacterials (environmental bacterial system to modify behavior based on external uptake). stimuli.

O CoA S Me n OH n O O O Me n CoA S OH

Efflux blockers - Target specific, not general.

Quorum sensing

Oxidative stress repair

Walsh, C. T. Antibiotics: Actions, Origins, Resistance, American Society for Microbiology Press, Washington DC, 2003, chapter 15

Quorum Sensing as a Novel Antibacterial Target

Two strategies may be possible to use quorum sensing as an antibacterial strategy:

Develop molecules that turn on QS-regulated genes early, allowing the immune response to eliminate the now-revealed intruder.

Develop antagonists that prevent QS-regulated genes from being turned on, preventing virulence.

Bonnie Bassler Princeton University check out TED talk!

www.ted.com/talks/bonnie_bassler_on_how_bacteria_communicate.html http://upload.wikimedia.org/wikipedia/commons/c/cf/Quorum_sensing_diagram.png http://www.advancedhealing.com/blog/wp-content/uploads/2009/12/Quorum_Sensing_Biofilm_Formation.gif Quinolones Stabilize the DNA-Gyrase Covalent Intermediate

Studies non-linear effects in systems biology

In 2007, showed that all bactericidal antibiotics kill bacteria by a common mechanism, oxidative damage from hydroxyl radicals

Suggests targeting RecA in order to potentiate current antibiotic therapies James J. Collins

Professor of biomedical engineering at Boston University

RecA - involved in DNA repair

Inhibitors currently being developed by Scott Singleton, professor at UNC

Wigle, T. J.; Singleton, S. F. Bioorg. Med. Chem. Lett. 17 (12): 3249–53. Collins, J. J. et. al. Cell. 2007, 130, 797-810

Nitric Oxide as Antibiotic Protection for Bacteria

+ H2N NH2

HO2C NH

NH2 L-

NADPH + O2 Evgeny Nudler

H2N N Professor of Biochemistry OH

NYU Langone Medical Center HO2C NH

NH2

NADPH + O2

H2N O O HO2C NH N

NH2 L-Citrulline Also H2S!

Nitric Oxide Synthase Nudler, E. A. et. al. Science 2009, 325, 1380-1384; Nudler, E. A. et. al. Science 2011, 334, 986-990 http://mycrains.crainsnewyork.com/40under40/profile_images/2008/photogallery/2008NudlerLevgeny_3.jpg Fin