The beta-lactam antibiotics are among the foremost chemotherapeutic agents in combatting bacterial infections in man. As a group they constitute more than 10% of ethical drug sales world-wide. Growing chemical and genetic information suggests that they can be divided into at least four biosynthetic classes. These groups present distinct and intriguing enzymatic solutions to the in vivo task of providing strained ring systems of high chemical potential and inhibitory specificity. Biosynthetic investigations are outlined relying on chemical, enzymatic and genetic methods to understand (1) monocyclic beta-lactam formation evident in the nocardicins and monobactams, (2) genesis of the important beta-lactamase inhibitor clavulanic acid and the related, antipodal clavams and, (3) creation of the carbapenem nucleus using carbapenem-3-carboxylate, the simplest member a family of more than 40 natural products, as the experimental system. While questions of fundamental interest in bioorganic chemistry will be addressed in these studies, valuable knowledge can be gained that lead to improved production of these important commodities, for example, through the incorporation of multiple copies of key biosynthetic genes in commercial fermentation strains, the possible use of immobilized enzymes or their site-specific mutants in synthesis or modification, and the development of improved structural types conferring antiobiotic activity against resistant bacterial strains.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI014937-20
Application #
2671695
Study Section
Bio-Organic and Natural Products Chemistry Study Section (BNP)
Project Start
1978-09-01
Project End
1999-03-31
Budget Start
1998-04-01
Budget End
1999-03-31
Support Year
20
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Long, Darcie H; Townsend, Craig A (2018) Mechanism of Integrated ?-Lactam Formation by a Nonribosomal Peptide Synthetase during Antibiotic Synthesis. Biochemistry 57:3353-3358
Oliver, Ryan A; Li, Rongfeng; Townsend, Craig A (2018) Monobactam formation in sulfazecin by a nonribosomal peptide synthetase thioesterase. Nat Chem Biol 14:5-7
Li, Rongfeng; Oliver, Ryan A; Townsend, Craig A (2017) Identification and Characterization of the Sulfazecin Monobactam Biosynthetic Gene Cluster. Cell Chem Biol 24:24-34
Harari, Colin M; Magagna, Michelle; Bedoya, Mariajose et al. (2016) Microwave Ablation: Comparison of Simultaneous and Sequential Activation of Multiple Antennas in Liver Model Systems. Radiology 278:95-103
Townsend, Craig A (2016) Convergent biosynthetic pathways to ?-lactam antibiotics. Curr Opin Chem Biol 35:97-108
Marous, Daniel R; Lloyd, Evan P; Buller, Andrew R et al. (2015) Consecutive radical S-adenosylmethionine methylations form the ethyl side chain in thienamycin biosynthesis. Proc Natl Acad Sci U S A 112:10354-8
Gaudelli, Nicole M; Long, Darcie H; Townsend, Craig A (2015) ?-Lactam formation by a non-ribosomal peptide synthetase during antibiotic biosynthesis. Nature 520:383-7
Gaudelli, Nicole M; Townsend, Craig A (2014) Epimerization and substrate gating by a TE domain in ?-lactam antibiotic biosynthesis. Nat Chem Biol 10:251-8
Buller, Andrew R; Freeman, Michael F; Schildbach, Joel F et al. (2014) Exploring the role of conformational heterogeneity in cis-autoproteolytic activation of ThnT. Biochemistry 53:4273-81
Li, Rongfeng; Lloyd, Evan P; Moshos, Kristos A et al. (2014) Identification and characterization of the carbapenem MM 4550 and its gene cluster in Streptomyces argenteolus ATCC 11009. Chembiochem 15:320-31

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