# FACTORS DETERMINING PROTEIN LOCALIZATION IN E. COLI

> **NIH NIH R01** · UNIV OF NORTH CAROLINA CHAPEL HILL · 1992 · $111,503

## Abstract

Proteins exported via the primary export pathway of the gram negative
bacterium Escherichia coli are synthesized as precursors with amino-
terminal signal peptides that are thought to have major roles in the export
process, including entry into the pathway and translocation across the
cytoplasmic membrane.  To date, many, perhaps all, of the protein
components of the export pathway have been identified.  However, the
precise role of these components and how they interact with one another,
membrane lipids, and the signal peptide and mature moiety of precursor
proteins to facilitate the export process have yet to be determined.  For
the past few years, our laboratory has been intensively investigating the
synthesis and secretion of the periplasmic maltose-binding protein (MBP) of
Escherichia coli using a combination of genetic and biochemical approaches.
Our long term goal is to understand, at the molecular level, the mechanism
by which the MBP is exported from its site of synthesis in the cytoplasm to
the periplasm.  The following are our specific aims for the proposed five
year project period:  (1) We will continue our analysis of the MBP signal
peptide with particular emphasis on the cleavage site and in understanding
why certain mutant signal peptides promote unusually rapid MBP export.  (2)
Studies on the cleavage site of preMBP have provided two new genetic
selections that may yield mutants with alterations in SPase I or other
known or unknown components of the export machinery.  (3) The recognition
and translocation of export-defective MBP species in E. coli cells
harboring various pr1 suppressor alleles will be investigated further.  (4)
We will determine if SecB specifically recognizes the mature moiety of
precursor MBP, or if such an interaction is not sequence specific and/or is
partly determined by the signal peptide or other factors.  (5) Experiments
are planned to distinguish between the chaperone and targeting functions of
SecB, including attempts to isolate mutations in secA or secB that
specifically inhibit the targeting activity.  (6) In an effort to
understand why some proteins are exported in a SecB-independent manner, we
will expand our studies addressing the localization of the periplasmic
ribose-binding protein.

## Key facts

- **NIH application ID:** 3127120
- **Project number:** 5R01AI017292-13
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **SAM.gov UEI:** D3LHU66KBLD5
- **Principal Investigator:** JANNE G CANNON
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1992
- **Award amount:** $111,503
- **Award type:** 5
- **Project period:** 1980-08-01 → 1994-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3127120

## Citation

> US National Institutes of Health, RePORTER application 3127120, FACTORS DETERMINING PROTEIN LOCALIZATION IN E. COLI (5R01AI017292-13). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3127120. Licensed CC0.

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