# Atomic-level probing of the peptidoglycan biosynthetic machinery in bacterial cell wall biogenesis

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA, SAN FRANCISCO · 2023 · $412,077

## Abstract

The emergence of microbes resistant to even the most powerful antibiotics represents a serious threat to
global public health. The coordinated action of the bacterial machinery of peptidoglycan (PG) synthesis, a
process essential for bacterial viability, represents an obvious target for the development of new antibiotics.
In this proposed project, we aim to define the molecular interactions of the components of the PG degradation
apparatus, consisting of enzymes involved in glycan chain hydrolysis or modification. Our previous studies in
Neisseria meningitidis showed that targeting a hot spot on a single lytic transglycosylase (LgtA) also disables
the function of the PG-modifying enzyme, Ape1, leading to a disruption of PG assembly, and results in an
aberrant peptidoglycan composition, making this pathogen unable to survive in the host. Our studies will
reveal, in molecular detail, how these peptidoglycan degrading enzymes work in concert to assemble the
bacterial cell wall. Specifically, we will define, in a comprehensive way, how a network of lytic
transglycosylases (LtgA, LtgD, LtgE) and their protein binding partners work to facilitate peptidoglycan
degradation and the insertion of organelles into the bacterial cell envelope. In this project, we will utilize
biochemical and biological approaches to probe protein-protein and enzyme-substate interactions of the
various lytic transglycosylases, combined with determination of the molecular basis of activity of the
multienzyme complexes in PG metabolism. Genetic modifications of the components of the PG biosynthetic
nanomachine will be used to test the observations from our structural studies. Our approach, utilizing high
resolution x-ray crystallographic tools along with cryo-EM single particle analysis, will allow visualization of
the action of enzymes in PG assembly and degradation and should provide mechanistic insights into their
orchestrated activity during the insertion of new PG during cell wall assembly and bacterial cell division. Our
studies will lead the way towards the development of new therapies targeting multiple peptidoglycan metabolic
enzymes.

## Key facts

- **NIH application ID:** 10685947
- **Project number:** 5R01GM144694-02
- **Recipient organization:** UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
- **Principal Investigator:** Allison H Williams
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $412,077
- **Award type:** 5
- **Project period:** 2022-09-01 → 2026-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10685947

## Citation

> US National Institutes of Health, RePORTER application 10685947, Atomic-level probing of the peptidoglycan biosynthetic machinery in bacterial cell wall biogenesis (5R01GM144694-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10685947. Licensed CC0.

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