This program investigates the role of protein-protein interactions in natural product modular synthases, a group of biosynthetic enzymes of three types: polyketide synthase (PKS), non-ribosomal peptide synthetase (NRPS), and fatty acid synthase (FAS). Many of these natural products serve as anti-cancer agents or antibiotics, while others are pathogenic toxins. Recent evidence indicates that protein-protein interactions between the carrier protein domain and catalytic domains of these pathways are key to proper catalysis and processivity. These critical interactions are transient in nature and remain largely uncharacterized. We have developed tools that allow synthetic modification of carrier protein domains, and here we leverage these tools to increase the lifetime of these protein-protein interactions using substrate mimics and covalent cross-linking inhibitors. These tools will allow us to visualize the molecular details by which carrier proteins bind tethered substrates prior to catalysis and how they interact with cognate catalytic domains. Through these studies, we intend to gain a more complete understanding of the dynamics of these catalytic events through analysis of solution phase NMR spectra. NMR perturbation comparisons of modified carrier proteins and titration experiments in the presence of catalytic domains will offer us an ability to accurately pinpoint the residues involved in substrate sequestration and protein-protein interaction. We will further validate our findings through site-directed mutagenesis, hydrogen/deuterium exchange NMR, and isothermal titration calorimetry. A deeper understanding of these protein-protein interactions will affect emerging fields in drug discovery. Using these tools to guide new interactions will enable combinatorial biosynthesis of new pharmacophores, while new drug targets may be discovered through abrogating these interactions in pathogen biosynthesis.
This program investigates the activity of modular synthases, a group of natural product biosynthetic enzymes of three types: polyketide synthase, non-ribosomal peptide synthase, and fatty acid synthase. These three subgroups are responsible for the production of antibiotics that represent major constituents of medicinal therapeutics, toxins that support pathogenesis for infection, and primary metabolites essential for life. These studies will benefit human health by enabling manipulation of these pathways to provide new therapeutic drugs and to identify new targets for drug design.
|Sarria, Stephen; Bartholow, Thomas G; Verga, Adam et al. (2018) Matching Protein Interfaces for Improved Medium-Chain Fatty Acid Production. ACS Synth Biol 7:1179-1187|
|Chen, Aochiu; Re, Rebecca N; Burkart, Michael D (2018) Type II fatty acid and polyketide synthases: deciphering protein-protein and protein-substrate interactions. Nat Prod Rep 35:1029-1045|
|Barajas, Jesus F; Shakya, Gaurav; Moreno, Gabriel et al. (2017) Polyketide mimetics yield structural and mechanistic insights into product template domain function in nonreducing polyketide synthases. Proc Natl Acad Sci U S A 114:E4142-E4148|
|Dick, Benjamin L; Patel, Ashay; McCammon, J Andrew et al. (2017) Effect of donor atom identity on metal-binding pharmacophore coordination. J Biol Inorg Chem 22:605-613|
|Finzel, Kara; Beld, Joris; Burkart, Michael D et al. (2017) Utilizing Mechanistic Cross-Linking Technology to Study Protein-Protein Interactions: An Experiment Designed for an Undergraduate Biochemistry Lab. J Chem Educ 94:375-379|
|Jaremko, Matt J; Lee, D John; Patel, Ashay et al. (2017) Manipulating Protein-Protein Interactions in Nonribosomal Peptide Synthetase Type II Peptidyl Carrier Proteins. Biochemistry 56:5269-5273|
|Vickery, Christopher R; La Clair, James J; Burkart, Michael D et al. (2016) Harvesting the biosynthetic machineries that cultivate a variety of indispensable plant natural products. Curr Opin Chem Biol 31:66-73|
|Mindrebo, Jeffrey T; Nartey, Charisse M; Seto, Yoshiya et al. (2016) Unveiling the functional diversity of the alpha/beta hydrolase superfamily in the plant kingdom. Curr Opin Struct Biol 41:233-246|
|McCulloch, Ian P; La Clair, James J; Jaremko, Matt J et al. (2016) Fluorescent Mechanism-Based Probe for Aerobic Flavin-Dependent Enzyme Activity. Chembiochem 17:1598-601|
|Rivera Jr, Heriberto; Dhar, Sachin; La Clair, James J et al. (2016) An unusual intramolecular trans-amidation. Tetrahedron 72:3605-3608|
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