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Probing Nature for Antibiotics
Irosha Nayanthika Nawarathne
Michigan State University
04/30/08
health.howstuffworks.com
Struggle for living
dansaper.blogspot.com, www.photos-screensaver-maker.com,
tecnocientista.info.com, www.creswell-crags.org.uk

“History of humankind can be regarded
from a medicinal point of view as a struggle
against infectious diseases”
Yoneyama, H., Katsumata, R., Biosci. Biotechnol. Biochem., 2006, 70,1060
Survival against infectious diseases
dodd.cmcvellore.ac.in, www.ayurvedicmedicine4u.com, www.rootsweb.com
What are antibiotics?
Molecules that stop the microbial growth (both bacteria
and fungi) or kill them outright
Walsh, C., Antibiotics Actions origins and Resistance, 2003, 4
How do the antibiotics act against bacteria?
Cell Wall Biosynthesis
β-lactams,Cyclosporins,Glycopeptides
Walsh, C., Antibiotics Actions origins and Resistance, 2003, 19
www.jacksofscience.com
How do the antibiotics act against bacteria?
Protein Biosynthesis
Aminoglycosides,Macrolides,
Tetracyclines,Oxazolidinones
Walsh, C., Antibiotics Actions origins and Resistance, 2003, 19
www.istockphoto.com
How do the antibiotics act against bacteria?
DNA Biosynthesis
Quinolones
RNA Biosynthesis
Rifampicin
Walsh, C., Antibiotics Actions origins and Resistance, 2003, 19
publications.nigms.nih.gov, www.istockphoto.com
How do the antibiotics act against bacteria?
Metabolic pathways
Folic Acid Metabolism
Trimethoprim, Sulfonamides
Fatty Acid Biosynthesis
Triclosan, Isoniazid, Ethionamide
Walsh, C., Antibiotics Actions origins and Resistance, 2003, 19
www.istockphoto.com
Why do we need more antibiotics?
- Developing antimicrobial resistance
Bacterial species
Common types of Antimicrobial
Resistance
Types of Infections
Streptococcus pneumoniae
β-lactams, cephalosporins, macrolides
Tetracyclines
Otitis media, pneumonia,
sinusitis, meningitis
Meticillin, cephalosporins, macrolides
Skin, soft tissue, sepsis
pneumonia
Healthcare-associated
Meticillin, cephalosporins, quinolones,
aminoglycosides, macrolides
Endocarditis, pneumonia,
sepsis
Enterococcus spp.
Ampicillin, vancomycin, aminoglycosides
Sepsis, urinary tract
Staphylococcus aureus
Community-associated
Furuya, E.Y., Lowy, F.D., Nature, 2006, 4, 36
What should be targeted?
The compounds with,

Novel structures

New modes of action
Fernandes, P., Nature Biotechnology, 2006, 24, 1497
Where do the antibiotics come from?
NATURE
Where do the antibiotics come from?
NATURE
NP
SS
TS
Where do the antibiotics come from?
NATURE
Helps in designing
the molecules
NP
SS
TS
Natural products as antibiotics


Naturally occurring compounds that are end products of secondary
metabolism.
Mostly extracted from plants, marine organisms, or microorganisms.
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Natural products as antibiotics



Naturally occurring compounds that are end products of secondary
metabolism.
Mostly extracted from plants, marine organisms, or microorganisms.
Eg:
Isolation - Streptomyces erythreus in 1952
Uses
- Respiratory tract diseases,
genital infections
MOA
- Inhibition of protein synthesis
Erythromycin
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Pal, S., Tetrahedron, 2006, 62, 3171
Antibiotics which are semi-synthesized

Synthetically modified chemical compounds which are originated
from natural products.
Walsh, C., Antibiotics Actions origins and Resistance, 2003, 4
Erythromycin is
Acid unstable
Pal, S., Tetrahedron, 2006, 62, 3171
Antibiotics which are semi-synthesized
Clarithromycin
TE802
Azithromycin
HMR3647
Pal, S., Tetrahedron, 2006, 62, 3171
Antibiotics which are totally from synthesis


Totally synthesized molecules which are potent as antibiotics.
Three main types.
1. Sulfa drugs
2. Quinolones
3. Oxazolidinones
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Antibiotics which are totally from synthesis

Sulfa drugs (Sulphonamides)
Sulfamethoxazole
Uses
- Urinary tract infections, pneumonia etc.
MOA
- Inhibition of folate synthesis
Harold, P.L., O’Grady, F.W., Antibiotic and Chemotherapy, 1992, 6, 268-272
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Antibiotics which are totally from synthesis

Sulfa drugs (Sulphonamides)
Sulfamethoxazole
Naturally occurring
p-aminobenzoic acid
Uses
- Urinary tract infections, pneumonia etc.
MOA
- Inhibition of folic acid biosynthesis
Harold, P.L., O’Grady, F.W., Antibiotic and Chemotherapy, 1992, 6, 268-272
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Walsh, C., Antibiotics Actions origins and Resistance, 2003, 80-82
Antibiotics which are totally from synthesis

Quinolones
Ciprofloxacin
Uses
MOA
- Urinary tract infections, Lower respiratory infections, Gastrointestinal
infections
- Inhibition of DNA synthesis
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Antibiotics which are totally from synthesis

Quinolones
Naturally occurring
Aurachin D
Ciprofloxacin
Aurachin C
Uses
MOA
- Urinary tract infections, Lower respiratory infections, Gastrointestinal
infections
- Inhibition of DNA synthesis
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Kunze, B., Hofle, G., Reichenbach, H., J. Antibiotics, 1987, 40, 258
Antibiotics which are totally from synthesis

Oxazolidinones
Linezolid
Uses
MOA
- Soft tissue infections, skin infections, Tuberculosis etc.
- Inhibition of protein synthesis
Ford, C.W., Zurenko, G.E., Barbachyn, M.R., Current Drug Targets-Infectious Disorders, 2001, 1,181
Antibiotics which are totally from synthesis

Oxazolidinones
Naturally occurring
(-)-Cytoxazone
Linezolid
(+)-Sreptazolin
Uses
MOA
- Soft tissue infections, skin infections, Tuberculosis etc.
- Inhibition of protein synthesis
Ford, C.W., Zurenko, G.E., Barbachyn, M.R., Current Drug Targets-Infectious Disorders, 2001, 1,181
Zappia, G., et al., Mini-Reviews in Medicinal Chemistry, 2007, 7, 389
Sources of antibacterial drugs
from 1981 to 2002
21%
1%
10%
NP
SS
TS
NM
68%
Newman, D.J., Cragg, G.M., Snader, K.M., J. Nat. Prod., 2003, 66, 1022
Ways of probing nature for antibiotics
NATURE
Approach A
By exploring the novel
Natural Products
Approach B
Generating
the Nature Mimics
Ways of probing nature for antibiotics
NATURE
Approach A
By exploring the novel
Natural Products
Approach B
Generating
the Nature Mimics
New antibiotics
New architectural scaffolds
Approach A
Conventional way of NP discovery
Extraction to the
solvents
Natural materials
Isolation and
Structure Elucidation
Bioassay guided fractionation
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
www.spc.int, www.oceanexplorer.noaa.gov, www.nature.com, www.textbookofbacteriology.net
Approach A
Conventional way of NP discovery
Why isn’t it successful?

Problems associated with the growth or the availability of the
source
Replication of the hits

Do not distinguish novel from old

Mostly miss the novel compounds due to the lack of sensitivity

No hints about MOA

Cannot reveal potency at screening stage

Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Clardy, J., Fischbach, M.A., Walsh, C., Nat. Rev. Biotechnol., 2006, 24, 1541
Approach A
What are the new strategies to explore nature for
NPs
Novel culturing techniques
Heterologous expression of biosynthetic genes &
Metagenomics
Molecular Biology
based Techniques
Genomics and Combinatorial biosynthesis
Precursor directed biosynthesis & Mutasynthesis
Differential sensitivity screening approach
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Clardy, J., Fischbach, M.A., Walsh, C., Nat. Rev. Biotechnol., 2006, 24, 1541
Donadio, S., Chemistry & Biology, 2006, 13, 560
Approach A
What are the new strategies to explore nature for
NPs
Novel culturing techniques
Heterologous expression of biosynthetic genes &
Metagenomics
Molecular Biology
based Techniques
Genomics and Combinatorial biosynthesis
Precursor directed biosynthesis & Mutasynthesis
Differential sensitivity screening approach
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Clardy, J., Fischbach, M.A., Walsh, C., Nat. Rev. Biotechnol., 2006, 24, 1541
Donadio, S., Chemistry & Biology, 2006, 13, 560
Approach A
Precursor Directed Biosynthesis & Mutasynthesis
Producing organisms
found in nature
Wild type
Mutant type
Extraction
to the
Solvents
Pathogen
Approach A
Precursor Directed Biosynthesis & Mutasynthesis
Wild type
Natural Biosynthetic pathway
Kennedy, J., Nat. Prod. Rep., 2008, 25, 25
Weist, S., Sϋssmuth, R. D., Appl. Microbiol. Biotechnol., 2005, 68, 141
Approach A
Precursor Directed Biosynthesis and Mutasynthesis
Wild type
Precursor-Directed Biosynthesis
Kennedy, J., Nat. Prod. Rep., 2008, 25, 25
Weist, S., Sϋssmuth, R. D., Appl. Microbiol. Biotechnol., 2005, 68, 141
Approach A
Precursor Directed Biosynthesis and Mutasynthesis
Mutant
Mutasynthon
Mutasynthesis
Kennedy, J., Nat. Prod. Rep., 2008, 25, 25
Weist, S., Sϋssmuth, R. D., Appl. Microbiol. Biotechnol., 2005, 68, 141
Approach A
Mutasynthesis
Ring A
Ring B
Ring C
Novobiocin (Albamycin)
Ring A
Ring B
Ring C
Clorobiocin
Pojer, F., Li, S.M., Heide, L., Microbiology, 2002, 148, 3901
Galm, U., et al, Chemistry & Biology, 2004, 11, 173
Weist, S., Sϋssmuth, R. D., Appl. Microbiol. Biotechnol., 2005, 68, 141
Approach A
Mutasynthesis
CloQ- mutants
Pojer, F., Li, S.M., Heide, L., Microbiology, 2002, 148, 3901
Galm, U., et al, Chemistry & Biology, 2004, 11, 173
Eustảquio, A.S., et al, Arch. Microbiol., 2003, 180, 25
Approach A
Mutasynthesis
Clorobiocin
CloQ-mutant
Galm, U., et al, Chemistry & Biology, 2004, 11, 173
Pojer, F., Li, S.M., Heide, L., Microbiology, 2002, 148, 3901
Approach A
Mutasynthesis
Clorobiocin
CloQ-mutant
Galm, U., et al, Chemistry & Biology, 2004, 11, 173
Pojer, F., Li, S.M., Heide, L., Microbiology, 2002, 148, 3901
Approach A
Mutasynthesis
CloQ-mutant
Analogs of Clorobiocin
Galm, U., et al, Chemistry & Biology, 2004, 11, 173
Galm, U., et al, Antimicrob. Agents Chemother., 2004, 48, 1307
Pojer, F., Li, S.M., Heide, L., Microbiology, 2002, 148, 3901
Approach A
What are the new strategies to explore nature for
NPs
Novel culturing techniques
Heterologous expression of biosynthetic genes &
Metagenomics
Molecular Biology
based Techniques
Genomics and Combinatorial biosynthesis
Precursor directed biosynthesis & Mutasynthesis
Differential sensitivity screening approach
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Clardy, J., Fischbach, M.A., Walsh, C., Nat. Rev. Biotechnol., 2006, 24, 1541
Donadio, S., Chemistry & Biology, 2006, 13, 560
Approach A
Differential sensitivity screening approach
Producing
organism from nature
Extraction
to the
solvents
Pathogen
Expression of
certain protein/s
Wild type
Normal
Disabled type
Low
Increased
sensitivity
Target the
pathway
Couzin, J., Nature, 2006, 314, 34, Forsyth
R.A., Molecular Biology, 2002, 43, 1387
Wang, J., et al, Antimicrob. Agents Chemother., 2006, 50, 519
Approach A
Differential sensitivity screening approach
Fatty Acid Biosynthesis… A good target
FAB Type I
- In mammals
FAB Type II
- In bacteria
Campbell, J.W., Cronan, J.E.Jr., Annu. Rev. Microbiol., 2001, 55, 305
Biosynthesis of Saturated Fatty Acids
Campbell, J.W., Cronan, J.E.Jr., Annu. Rev. Microbiol., 2001, 55, 305
Biosynthesis of Saturated Fatty Acids
Campbell, J.W., Cronan, J.E.Jr., Annu. Rev. Microbiol., 2001, 55, 305
Biosynthesis of Saturated Fatty Acids
Campbell, J.W., Cronan, J.E.Jr., Annu. Rev. Microbiol., 2001, 55, 305
Approach A
Differential sensitivity screening approach
RNA-mediated gene silencing technique
5` ………ATGGCCTGGACTTCA…………3` Sense DNA
3` ………TACCGGACCTGAAGT…………5` Antisense DNA
Transcription
5` ………AUGGCCUGGACUUCA…………3`
mRNA
Translation
Met - Ala - Trp - Thr - Ser -
Peptide
Singh, S.B., et al, J. Am. Chem. Soc., 2006, 128, 11916
Forsyth, R.A., Molecular Biology, 2002, 43, 1387
Wang, J., et al, Antimicrob. Agents Chemother., 2006, 50, 519
Antisense RNA
Approach A
Differential sensitivity screening approach
RNA-mediated gene silencing technique
In Prokaryotes-
5`……… AUGGCCUGGACUUCA………3`
3`……… UACCGGACCTGTTGU ………5`
ds RNA
Degradation of fabF mRNA or inhibition of translation
Reduced or No FabF expression
Higher sensitivity towards FabF inhibitors
Singh, S.B., et al, J. Am. Chem. Soc., 2006, 128, 11916
Forsyth, R.A., Molecular Biology, 2002, 43, 1387
Wang, J., et al, Antimicrob. Agents Chemother., 2006, 50, 519
Approach A
Differential sensitivity screening approach
Results - RNA-mediated gene silencing technique
Wild type
fabF Anti-sense
Inhibitor (μg)
Wang, J., et al, Nature, 2006, 441, 358
Approach A
Differential sensitivity screening approach
Results - RNA-mediated gene silencing technique
Wild type
fabF Anti-sense
200 times more potent
than Cerulenin
Wild type
fabF Anti-sense
Inhibitor (μg)
Wang, J., et al, Nature, 2006, 441, 358
Price, A.C., et al, The Journal of Biological Chemistry, 2001, 276, 6551
Heath, R.J., White, S.W., Rock, C.O., Progress in Lipid Research, 2001, 40, 467
Approach A
Differential sensitivity screening approach
Discovery of Platensimycin
OH
O
HO
O
OH
O
N
H
O
Platensimycin
from a strain of Streptomyces platensis
Singh, S.B., et al, J. Am. Chem. Soc., 2006, 128, 11916
Approach A
Differential sensitivity screening approach
Potency of Platensimycin
Organism and genotype
Platensimycin
Antibacterial activity
(MIC, µg/ml)
S. aureus (MSSA)
S. aureus (MRSA)
S. aureus (MRSA, macrolideR)
S. aureus (MRSA, linezolidR)
Enterococcus faecium (VRE)
0.5
0.5
0.5
1
0.1
Toxicity
HeLa MTT (IC50)
Linezolid
4
2
2
32
2
(µg/ml)
>1,000
>100
MIC – Concentration of inhibitor used to result no visible growth of the pathogens
IC50 – Concentration of the inhibitor used to kill 50% population of the living cells
Wang, J., et al, Nature, 2006, 441, 358
Approach A
Differential sensitivity screening approach
High FabF selectivity
O
O
HO

O
FabD
SCoA
Cell - free gel - elongation assay
HO
ACPSH
O
O
S
ACP
CoA
CoASH
FabH
C02 + CoASH
O
Malonyl-ACP
C4:1(Δ2)-ACP
C4:0-ACP
O
S
ACP
NADPH
FabG
NADP
CO 2 + ACPSH
OH
O
S
FabA
FabZ
FabF
>6C-ACP
ACP
H 2O
O
S
O
HO
NADPH
O
S
ACP
NADP
FabI
FabK
FabL
O
S
Wang, J., et al, Nature, 2006, 441, 358
Heath, R.J., Nat.Prod.Rep., 2002, 19, 581
ACP
ACP
Ways of probing nature for antibiotics
NATURE
Approach A
By exploring the novel
Natural Products
Approach B
Generating
the Nature Mimics
New antibiotics
New architectural scaffolds
Approach B
Generating Nature Mimics
Biosynthetic pathway
Enzyme purification &
3D structural determination
Designing theoretical chemical space that fits the active site or
docking the database structures
Translate to a real structure by synthesis
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Clardy, J., Fischbach, M.A., Walsh, C., Nat. Rev. Biotechnol., 2006, 24, 1541
Approach B
Generating Nature Mimics
Biosynthesis of lysine… A good target
 Essential for the bacterial growth
 Does not exist in mammals
Hutton, C.A., Perugini, M.A., Gerrard, J.A., Mol. Biosyst., 2007, 3, 458
Hutton, C.A., Southwood, T.J., Turner, J.J., Mini-Reviews in Medicinal Chemistry, 2003, 3,115
Biosynthesis of lysine
methionine
threonine
isoleucine
Hutton, C.A., Perugini, M.A., Gerrard, J.A., Mol. Biosyst., 2007, 3, 458
Hutton, C.A., Southwood, T.J., Turner, J.J., Mini-Reviews in Medicinal Chemistry, 2003, 3,115
Biosynthesis of lysine
methionine
threonine
isoleucine
Hutton, C.A., Perugini, M.A., Gerrard, J.A., Mol. Biosyst., 2007, 3, 458
Hutton, C.A., Southwood, T.J., Turner, J.J., Mini-Reviews in Medicinal Chemistry, 2003, 3,115
Approach B
Generating Nature Mimics
Proposed mechanism
Hutton, C.A., Perugini, M.A., Gerrard, J.A., Mol. Biosyst., 2007, 3, 458
Hutton, C.A., Southwood, T.J., Turner, J.J., Mini-Reviews in Medicinal Chemistry, 2003, 3,115
Approach B
Generating Nature Mimics
Supportive data
Acyl-enzyme intermediate
(Streptococcus pneumoniae)
Faehnle, C.R., Coq, J.L., Liu, X., Viola, R.E., Journal of Biological Chemistry, 2006, 281, 31031
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Hutton, C.A., Southwood, T.J., Turner, J.J., Mini-Reviews in Medicinal Chemistry, 2003, 3,115
Approach B
Generating Nature Mimics
Inhibitors of lysine biosynthesis
Cox, R.J., Gibson, J.S., Martín, M.B.M., Chem. Commun., 2001, 1710
Cox, R.J., Gibson, J.S., Hadfield, A.T., ChemBioChem, 2005, 6, 2255
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Approach B
Generating Nature Mimics
Inhibitors of lysine biosynthesis
Cox, R.J., Gibson, J.S., Martín, M.B.M., Chem. Commun., 2001, 1710
Cox, R.J., Gibson, J.S., Hadfield, A.T., ChemBioChem, 2005, 6, 2255
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Approach B
Generating Nature Mimics
In vitro assays
Reverse Biosynthesis
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Cox, R.J., Gibson, J.S., Hadfield, A.T., ChemBioChem, 2005, 6, 2255
Approach B
Generating Nature Mimics
Competitive assays
Direct assay
KI (ASA)
-
KI (Phosphate)
-
750 μM
2130μM
214 μM
92μM
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Blanco, J., Moore, R.A., Viola, R.E., PNAS, 2003, 100, 12613
Han, S., Moore, R.A., Viola, R.E., Synlett, 2003, 6, 845
Approach B
Generating Nature Mimics
Competitive assays
Direct assay
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Blanco, J., Moore, R.A., Viola, R.E., PNAS, 2003, 100, 12613
Han, S., Moore, R.A., Viola, R.E., Synlett, 2003, 6, 845
Approach B
Generating Nature Mimics
Competitive assays
Direct assay
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Blanco, J., Moore, R.A., Viola, R.E., PNAS, 2003, 100, 12613
Han, S., Moore, R.A., Viola, R.E., Synlett, 2003, 6, 845
Approach B
Generating Nature Mimics
Competitive assays
Direct assay
KI (ASA)
KI (Phosphate)
2nd pKa
-
4.2-5.0
750 μM
2130μM
6.1
214 μM
92μM
6.2-6.4
-
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Blanco, J., Moore, R.A., Viola, R.E., PNAS, 2003, 100, 12613
Han, S., Moore, R.A., Viola, R.E., Synlett, 2003, 6, 845
Approach B
Generating Nature Mimics
Time-dependent inhibition assays
Pre-incubation assay
KI (ASA)
95μM
-
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Blanco, J., Moore, R.A., Viola, R.E., PNAS, 2003, 100, 12613
Han, S., Moore, R.A., Viola, R.E., Synlett, 2003, 6, 845
Approach B
Generating Nature Mimics
Time-dependent inhibition assays
Pre-incubation assay
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Blanco, J., Moore, R.A., Viola, R.E., PNAS, 2003, 100, 12613
Han, S., Moore, R.A., Viola, R.E., Synlett, 2003, 6, 845
Ways of probing nature for antibiotics
NATURE
Approach A
By exploring the novel
Natural Products
Approach B
Generating
the Nature Mimics
New antibiotics
New architectural scaffolds
Please, Don’t flush!
 Average american receives more than 11 prescriptions a year.
 About 3.3 billion a total.
 Nonprescription drugs !
Halford, B., C & EN News, 2008, 86, 13
Halford, B., C & EN News, 2008, 86, 16
Acknowledgement
Dr. Walker
Dr. Hausinger
Dr. Arnosti
Dr. Stoltzfus
Dr. Stephen Soisson, Dr. Jun Wang (Merck)
Labmates - Behnaz, Danielle, Joshua, Mark, Washington, Yemane
Friends
- Samantha, Sue, Tharanga, Xiaofei
Thank you all !
Back-up slides
Approach A
Differential sensitivity screening approach
In vivo studies of Platensimycin
In a mouse model of disseminated S. aureus infection
Wang, J., et al, Nature, 2006, 441, 358
Timeline of discovery of novel classes of
antibiotics and introduction in clinic
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Approach B
Generating the Nature Mimics
Faehnle, C.R., Coq, J.L., Liu, X., Viola, R.E., Journal of Biological Chemistry, 2006, 281, 31031
Hutton, C.A., Perugini, M.A., Gerrard, J.A., Mol. Biosyst., 2007, 3, 458
Hutton, C.A., Southwood, T.J., Turner, J.J., Mini-Reviews in Medicinal Chemistry, 2003, 3,115
Antibiotics which are totally from synthesis

Sulfa drugs (Sulphonamides)
Naturally occurring
Sulfamethoxazole
Uses
- Urinary tract infections, pneumonia etc.
MOA
- Inhibition of folate synthesis
p-aminobenzoic acid
Harold, P.L., O’Grady, F.W., Antibiotic and Chemotherapy, 1992, 6, 268-272
Singh, S.B., Barrett, J.F., Biochemical Pharmacology, 2006, 71, 1006
Walsh, C., Antibiotics Actions origins and Resistance, 2003, 80-82
Approach A
Precursor Directed Biosynthesis
Penicillium
Chrysogenum
6-APA
(Penicillium notatum)
Nayer, J.H.C., Trends. Biochem. Sci., 1991, 16, 195
Nayer, J.H.C., Trends. Biochem.Sci., 1991, 16, 234
Kennedy, J., Nat. Prod. Rep., 2008, 25, 25
Approach A
Precursor Directed Biosynthesis
Penicillin G
Penicillium
Chrysogenum
(Penicillium notatum)
Penicillin V
Nayer, J.H.C., Trends. Biochem. Sci., 1991, 16, 195
Nayer, J.H.C., Trends. Biochem.Sci., 1991, 16, 234
Kennedy, J., Nat. Prod. Rep., 2008, 25, 25
Approach A
Mutasynthesis
Nov L
Ring A
Ring B
Ring C
Novobiocin (Albamycin)
Clo L
Ring A
Ring B
Ring C
Clorobiocin
Pojer, F., Li, S.M., Heide, L., Microbiology, 2002, 148, 3901
Galm, U., et al, Chemistry & Biology, 2004, 11, 173
Eustảquio, A.S., et al, Arch. Microbiol., 2003, 180, 25
Where do the antibiotics come from?
Kekule stucture of benzene
NATURE
NP
SS
TS
www.boomeria.org
Approach A
Precursor Directed Biosynthesis
Drawbacks

Involves complex purification procedures

Require high concentrations of synthetic precursor

Only few intermediates will incorporate into the product
Kennedy, J., Nat. Prod. Rep., 2008, 25, 25
Weist, S., Sϋssmuth, R. D., Appl. Microbiol. Biotechnol., 2005, 68, 141
Inhibitors of Fatty Acids Biosynthesis
Triclosan,
Isoniazid,
Ethionamide
Continues...
Cerulenin,
Thiolactomycin
Campbell, J.W., Cronan, J.E.Jr., Annu.Rev.Microbiol., 2001, 55, 305
Price, A.C., et al, The Journal of Biological Chemistry, 2001, 276, 6551
Heath, R.J., White, S.W., Rock, C.O., Progress in Lipid Research, 2001, 40, 467
Where do the antibiotics come from?
NATURE
Approach B
Generating the Nature Mimics
Cox, R.J., Gibson, J.S., Martín, M.B.M., Chem. Commun., 2001, 1710
Cox, R.J., Gibson, J.S., Hadfield, A.T., ChemBioChem, 2005, 6, 2255
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Approach B
Generating the Nature Mimics
Direct assay
Cox, R.J., Gibson, J.S., Martín, M.B.M., ChemBioChem, 2002, 3, 874
Blanco, J., Moore, R.A., Viola, R.E., PNAS, 2003, 100, 12613
Han, S., Moore, R.A., Viola, R.E., Synlett, 2003, 6, 845
Biosynthesis of Saturated Fatty Acids
FabI / K / L
ACP
FabD
FabZ
FabH
FabG
Campbell, J.W., Cronan, J.E.Jr., Annu. Rev. Microbiol., 2001, 55, 305
Biosynthesis of Saturated Fatty Acids
FabI / K / L
Continues...
FabD
FabZ
FabF
FabG
Campbell, J.W., Cronan, J.E.Jr., Annu. Rev. Microbiol., 2001, 55, 305