# MECHANISTIC STUDIES OF BACTERIAL CHEMOTAXIS

> **NIH NIH R01** · UNIVERSITY OF OREGON · 1990 · $139,432

## Abstract

During bacterial chemotaxis, cells such as Escherichia coli detect
temporal changes in the concentration of specific chemicals and respond
to these changes by modulation of the sense of rotation of the flagellar
rotary motors. The response appears to consist of two phases, an
"excitatory" phase which signals the flagella motors to rotate in the
appropriate sense and an "adaptive" phase during which the flagellar
signal is counteracted. The pathway for information flow is becoming
clear. It appears that a series of phosphoryl transfer reactions are
responsible for the excitatory phase and this pathway feeds back onto
the adaptive pathway by modulating the activity of methylesterase
enzyme, CheB, which regulates the methylation level of the receptor
proteins which in turn controls the signalling properties of the
receptor. This proposal is concerned with defining the chemical
mechanism of information flow from the receptors to the flagella and to
CheB. Muc of the focus of this proposal concerns CheB. This
multifunction enzyme acts as an amidase, methylesterase and as a
phosphatase, atcepting phosphate moieties from the excitatory pathway
and hydrolysing those phosphates. In turn the methylesterase activity of
CheB is likely to be regulated by its phosphorylation state. A series of
genetic and biochemical approaches are outlined to define how CheB
interacts with the excitatory pathway and to define how the methylation
state and ligand occupancy state of the receptors interact to generate
the excitatory signals.

## Key facts

- **NIH application ID:** 3127448
- **Project number:** 5R01AI017808-10
- **Recipient organization:** UNIVERSITY OF OREGON
- **SAM.gov UEI:** Z3FGN9MF92U2
- **Principal Investigator:** Frederick W. Dahlquist
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1990
- **Award amount:** $139,432
- **Award type:** 5
- **Project period:** 1981-04-01 → 1994-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3127448

## Citation

> US National Institutes of Health, RePORTER application 3127448, MECHANISTIC STUDIES OF BACTERIAL CHEMOTAXIS (5R01AI017808-10). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3127448. Licensed CC0.

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