# Peptidoglycan binding protein specificity and bacterial cell division

> **NIH NIH R01** · UNIVERSITY OF IOWA · 2021 · $328,751

## Abstract

Cell division in bacteria requires the concerted action of a large number of proteins that form a complex called
the septal ring. Major challenges for the future include identifying all of these proteins and determining what
they do on a biochemical level. Our long-term goal is to identify and characterize previously overlooked
bacterial proteins that are important for cell division. Here we focus on a new class of cell division proteins that
contain a “SPOR” domain. SPOR domains are found in over 3000 proteins from over 1000 bacterial species,
including many serious pathogens. SPOR domains bind septal peptidoglycan (PG) and thereby target many
division proteins to the division septum. The specific form of PG to which SPOR domains bind is a “denuded”
glycan, a region of the amino sugar backbone of PG devoid of peptide side-chains. This unusual targeting
mechanism sets SPOR domain proteins apart from the many septal ring proteins that localize via protein-
protein interactions. This study will use four Escherichia coli SPOR domain proteins (DamX, DedD, FtsN and
RlpA) to test two interrelated hypotheses: (a) different SPOR domains bind denuded glycans differently, and
(b) these differences are physiologically important. In Aim 1 biolayer interferometry (BLI) and isothermal
titration calorimetry (ITC) will be used to determine the affinity of SPOR domains for denuded glycans and the
features of the glycan that are important for binding. In addition, NMR will be used to determine the first
structure of a SPOR domain in complex with a PG ligand. In Aim 2, the four E. coli SPOR domain proteins will
be examined in vivo using sophisticated single-molecule microscopy methods. Objectives of this aim include
ascertaining whether different SPOR domain proteins localize to different sites at the septum and developing a
more detailed picture of the overall architecture of the septal ring. Aim 3 will focus on the structure and function
of DamX, using domain swapping and deletion analysis to identify important domains in that protein, ascribe
those domains to specific functions and determine whether SPOR domains are functionally interchangeable.
These experiments will connect the biochemistry and microscopy in Aims 1 & 2 to the actual function of SPOR
domain proteins during cell division. Particular effort will be devoted to understanding the mechanism by which
DamX inhibits cell division, because this is an unusual activity for a septal ring protein and may be relevant to
pathogenesis by E. coli that infect the bladder.

## Key facts

- **NIH application ID:** 10246987
- **Project number:** 5R01GM125656-04
- **Recipient organization:** UNIVERSITY OF IOWA
- **Principal Investigator:** DAVID S WEISS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $328,751
- **Award type:** 5
- **Project period:** 2018-09-17 → 2024-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10246987

## Citation

> US National Institutes of Health, RePORTER application 10246987, Peptidoglycan binding protein specificity and bacterial cell division (5R01GM125656-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10246987. Licensed CC0.

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