# Malonyl-thioester Isosteres to Determine Enzyme Structure-Function Relationships - Undergrad Supplement

> **NIH NIH R01** · PURDUE UNIVERSITY · 2021 · $8,009

## Abstract

Abstract:
Malonyl-thioesters are one of the major reactive intermediates in the biosynthesis of fatty acids
and polyketides. Because fatty acids are essential to cellular life, the inhibition of fatty acid
synthases is a viable mechanism for the generation of antimicrobials, anticancer agents and
control of metabolic disease. Polyketides on the other hand are widely used as antibiotics and
anticancer agents, making polyketide synthases targets for enzyme engineering. While most
intermediates in fatty acid and polyketide biosynthesis are used in reversible reactions, malonyl-
thioesters are created in and used in essentially irreversible reactions. This makes studying the
enzyme:malonyl-thioester interactions virtually impossible because the malonyl-thioesters are
destroyed in the process. To overcome this problem analogs of malonyl-thioesters were
generated by other researchers. These analogs replace the thioester ketone with a thioether or
oxetane, both of which are stable to enzymatic activity. However, neither of these analogs bind
in enzyme active sites in catalytically relevant orientations. Thus, there is a critical need to
develop stable malonyl-thioester isosteres capable of binding in enzyme active sites to elucidate
molecular interactions and conformational changes leading to efficient catalysis. The objective
of this proposal is to overcome problems associated with the natural malonyl-thioesters and
previously synthesized isosteres. We have a panel of malonyl-thioesters that preserve a key
ketone lost in the previous isosteres. Our first aim is to solve crystal or cryo-EM structures of
acyl-CoA carboxylase enzymes in complex with our best isosteres to elucidate the
enzyme:substrate interactions and conformational changes. Our second aim is to solve crystal,
cryo-EM or NMR structures of β-ketoacyl synthase enzymes in complex with our best isosteres
to elucidate enzyme:substrate interactions and conformational changes. Together these studies
will validate the use of malonyl-thioester analogs with carboxylate isosteres to capture
enzyme:substrate interactions. Our structures will reveal conformational changes during
catalysis that can be targeted for drug design and that need to be accounted for during enzyme
engineering.

## Key facts

- **NIH application ID:** 10393793
- **Project number:** 3R01GM140290-01S1
- **Recipient organization:** PURDUE UNIVERSITY
- **Principal Investigator:** Jeremy Ray Lohman
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $8,009
- **Award type:** 3
- **Project period:** 2020-09-20 → 2024-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10393793

## Citation

> US National Institutes of Health, RePORTER application 10393793, Malonyl-thioester Isosteres to Determine Enzyme Structure-Function Relationships - Undergrad Supplement (3R01GM140290-01S1). Retrieved via AI Analytics 2026-06-12 from https://api.ai-analytics.org/grant/nih/10393793. Licensed CC0.

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