# BIOSYNTHESIS OF BACTERIAL CELL WALL COMPONENTS

> **NIH NIH R01** · NORTHWESTERN UNIVERSITY · 1994 · $214,744

## Abstract

The primary goal of our research program is directed towards an
understanding of the biosynthesis and function of D-alanyl-lipoteichoic
acid (LTA), a macroamphiphile which plays a vital role in the growth and
development of the bacterium.  The chemical properties and cellular
location of this polymer indicate that it functions in the assembly of
the cell wall.  The substitution of the hydrophilic moiety of LTA with
D-alanine ester provided a mechanism for controlling the anionic charge.
Our hypothesis is that the D-alanine esters of LTA play a role in
determining cell shape and separation by regulating extramembranal
cellular functions.  Three areas of research will include:  (a)
establishment of the genetic organization of the operon for D-alanine
ester formation; (b) delineation of the mechanism of D-alanine
incorporation into LTA; (c) construction of defined genetic systems which
can be used to effect changes in the D-alanine ester content.

(a) The detailed characterization of the genetic components required for
D-alanyl ester formation is a prerequisite for understanding LTA
function.  Thus, it is our aim to:  (i) define the regulatory elements
and limits of the operon; (ii) identify the genes of the operon; (iii)
locate the gene for the D-alanine carrier protein (Dcp).

(b) D-Alanine-Dcp ligase catalyzes the activation of D-alanine and its
ligation to Dcp.  Our goal is to understand the enzymic  mechanism for
the thiolesterification of the 4'-phosphopantetheine prosthetic group of
Dcp with D-alanine.  It is also our goal to identify the membrane
proteins and carrier lipid that accept activated D-alanine from D-alanyl-
Dcp.  Because of the central importance of the carrier protein in the
incorporation pathway, studies of its structure and function are
necessary for identifying the specificity determinants that regulate its
role as an acceptor and as a donor of activated D-alanine.

(c) Based on the observations form part (a) and (b), our goal is to
design isogenic mutants which will aid in the determination of the in
vivo function of D-alanyl-LTA.  These constructions will provide strains
in which the LTA is either deficient or elevated in D-alanine ester
content.  The ability to modulate the ester content using genetically
defined mutants will clarify the role of these esters in the
determination of cell shape and separation.

Each of the aims described in this proposal is designed to provide a
detailed biochemical, genetic and structural understanding of D-alanyl-
LTA biosynthesis.  Achieving these goals will yield insights into the
role of these macroamphiphiles in the physiology of the gram-positive
bacterium.  The elucidation of the D-alanine incorporation system will
identity new targets which may be used for the rational design of
antibacterial agents.

## Key facts

- **NIH application ID:** 2190281
- **Project number:** 1R01GM051621-01
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **SAM.gov UEI:** EXZVPWZBLUE8
- **Principal Investigator:** FRANCIS C NEUHAUS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $214,744
- **Award type:** 1
- **Project period:** 1994-07-01 → 1998-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2190281

## Citation

> US National Institutes of Health, RePORTER application 2190281, BIOSYNTHESIS OF BACTERIAL CELL WALL COMPONENTS (1R01GM051621-01). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/2190281. Licensed CC0.

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