Polyketide synthases (PKSs) use a multi-step process to generate structurally complex natural products with wide ranging pharmaceutical and agricultural applications. Over the past decade there has been significant interest and notable successes in the generation of hybrid PKSs. These metabolic systems are attractive due to their potential to generate new natural products with valuable applications including drug discovery and development. Nonetheless, a significant and unresolved problem in this endeavor has been the significant finding that hybrid modular PKS systems are either catalytically inefficient, or simply inactive. The ongoing discovery of natural product biosynthetic gene clusters has recently provided new sets of genetic tools for the generation of more efficient hybrid PKSs. Recent advances in methods for genetic manipulation of large biosynthetic gene clusters now permit rapid generation of libraries of hybrid systems, and bioactivity assays can be used to identify those with significant catalytic activity. We have also developed a new chemoenzymatic approach for generating novel polyketide structures that can utilize both native and hybrid PKSs. This project will capitalize on these recent advances and demonstrate how they can be applied and combined to generate new biologically active macrolide antibiotics. The work will be based on the pikromycin PKS (Pik PKS) that generates a ketolide macrolactone core molecule (a class of antibiotics useful for treatment of multidrug resistant pathogens). The four specific aims are as follows: 1) chemoenzymatic synthesis of new macrolide products; 2) relaxing the specificity, and evolving iterative properties of ketoacyl acyl carrier protein synthase domains; 3) developing new methods for efficient initiation utilizing different substrates; and 4) efficiently and selectively altering extender unit specificity. Overall this project will provide new techniques and genetic tools that can be applied to other PKSs systems, including catalytically impaired hybrid PKSs, and will represent an important step towards the ultimate goal of using of combinatorial biosynthesis and chemoenzymatic synthesis for practical drug development. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM076477-01
Application #
7023404
Study Section
Special Emphasis Panel (ZRG1-BCMB-B (02))
Program Officer
Jones, Warren
Project Start
2006-01-10
Project End
2009-12-31
Budget Start
2006-01-10
Budget End
2006-12-31
Support Year
1
Fiscal Year
2006
Total Cost
$408,058
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Pharmacology
Type
Schools of Pharmacy
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Slocum, Samuel T; Lowell, Andrew N; Tripathi, Ashootosh N et al. (2018) Chemoenzymatic Dissection of Polyketide ?-Branching in the Bryostatin Pathway. Methods Enzymol 604:207-236
Skiba, Meredith A; Maloney, Finn P; Dan, Qingyun et al. (2018) PKS-NRPS Enzymology and Structural Biology: Considerations in Protein Production. Methods Enzymol 604:45-88
Lowell, Andrew N; DeMars 2nd, Matthew D; Slocum, Samuel T et al. (2017) Chemoenzymatic Total Synthesis and Structural Diversification of Tylactone-Based Macrolide Antibiotics through Late-Stage Polyketide Assembly, Tailoring, and C-H Functionalization. J Am Chem Soc 139:7913-7920
Hansen, Douglas A; Koch, Aaron A; Sherman, David H (2017) Identification of a Thioesterase Bottleneck in the Pikromycin Pathway through Full-Module Processing of Unnatural Pentaketides. J Am Chem Soc 139:13450-13455
Koryakina, Irina; Kasey, Christian; McArthur, John B et al. (2017) Inversion of Extender Unit Selectivity in the Erythromycin Polyketide Synthase by Acyltransferase Domain Engineering. ACS Chem Biol 12:114-123
Koch, Aaron A; Hansen, Douglas A; Shende, Vikram V et al. (2017) A Single Active Site Mutation in the Pikromycin Thioesterase Generates a More Effective Macrocyclization Catalyst. J Am Chem Soc 139:13456-13465
Tripathi, Ashootosh; Choi, Si-Sun; Sherman, David H et al. (2016) Thioesterase domain swapping of a linear polyketide tautomycetin with a macrocyclic polyketide pikromycin in Streptomyces sp. CK4412. J Ind Microbiol Biotechnol 43:1189-93
DeMars 2nd, Matthew D; Sheng, Fang; Park, Sung Ryeol et al. (2016) Biochemical and Structural Characterization of MycCI, a Versatile P450 Biocatalyst from the Mycinamicin Biosynthetic Pathway. ACS Chem Biol 11:2642-54
Hansen, Douglas A; Koch, Aaron A; Sherman, David H (2015) Substrate controlled divergence in polyketide synthase catalysis. J Am Chem Soc 137:3735-8
Chemler, Joseph A; Tripathi, Ashootosh; Hansen, Douglas A et al. (2015) Evolution of Efficient Modular Polyketide Synthases by Homologous Recombination. J Am Chem Soc 137:10603-9

Showing the most recent 10 out of 46 publications