# The mechanism of autolysin regulation in Vibrio cholerae

> **NIH NIH R01** · CORNELL UNIVERSITY · 2020 · $316,774

## Abstract

Project Summary
Most bacteria maintain a cell wall, an essential, mesh-like structure mainly comprising the polysaccharide
peptidoglycan (PG). Some of our most powerful antibiotics, the beta lactams (penicillins, carbapenems and
cephalosporins) target enzymes required for cell wall synthesis and derive their efficacy from their ability to not
only inhibit cell wall biogenesis, but also to actively cause its disruption. Cell wall disruption after exposure to
beta lactams is mediated by “autolysins”, a group of enzymes (amidases, lytic transglycosylases and
endopeptidase) with the capacity to cut a variety of chemical bonds within the PG mesh. Under normal growth
conditions, autolysins engage in important cell wall remodeling functions, such as PG mesh expansion during
cell elongation; how these functions are regulated to ensure proper PG maintenance is poorly understood. We
have shown that in the diarrheal pathogen Vibrio cholerae, the endopeptidases (EPs) ShyA and ShyC are
required for cell elongation during normal growth (the physiological functions of another paralogue, ShyB, are
unknown), but are also key factors mediating cell wall breakdown after exposure to beta lactam antibiotics.
How ShyA and ShyC are regulated to ensure proper cell wall maintenance in the absence of antibiotics is
unknown. Here, we propose experiments to build a thorough understanding of mechanisms of endopeptidase
regulation in V. cholerae on multiple levels. Since M23 EPs are well-conserved throughout Bacteria, our
experiments will likely yield insights with broad relevance to other pathogens. In Aim 1, we will dissect the
functional relationship between PG synthesis and degradation processes. We will also test the hypothesis that
ShyA and ShyC's direct interaction with cell wall synthesis complexes regulates their activity. In Aim 2 we will
precisely map structure-function relationships in EPs and discover additional regulators of their activity. In Aim
3 we will determine the mechanism of EP regulation by metal homeostasis. Taken together, these experiments
will provide us with an extensive framework of how an important human pathogen maintains the balance
between cell wall synthesis and remodeling, with the goal of discovering new potential targets for antibiotics
that modulate autolysin activity.

## Key facts

- **NIH application ID:** 10000951
- **Project number:** 5R01GM130971-02
- **Recipient organization:** CORNELL UNIVERSITY
- **Principal Investigator:** Tobias Doerr
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $316,774
- **Award type:** 5
- **Project period:** 2019-09-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10000951

## Citation

> US National Institutes of Health, RePORTER application 10000951, The mechanism of autolysin regulation in Vibrio cholerae (5R01GM130971-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10000951. Licensed CC0.

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