# ATP-COUPLED ARSENICAL PUMP OF ESCHERICHIA COLI

> **NIH NIH R01** · WAYNE STATE UNIVERSITY · 1992 · $236,942

## Abstract

The overall goals of this research are first, elucidation of the
molecular mechanisms of an ion pump whose genes are natural components of
a bacterial resistance plasmid, and second, the role of this transport
system in bacterial resistance to antibiotics and toxic compounds.  A
bacterial anion-translocating TPase has been identified as the product of
the arsenical resistance (ars) operon of resistance plasmid R773.  When
expressed in Escherichia coli the ATP-driven pump catalyzes extrusion of
the oxyanions arsenite, antimonite, and arsenate, thus providing
resistance to the toxic compounds.  This anion-translocating ATPase
serves as an excellent model system for ion-translocating ATPases.

The ars operon has been cloned and sequenced, and most of the protein
components have been identified-and purified.  Two of the structural
genes, the arsA and arsB genes, encode the two subunits of the pump.
This two-component inner membrane complex binds and transports arsenite
and antimonite, oxyanions with the +III oxidation state of arsenic or
antimony.  Specific aims of the project include determination of the
structural elements of the ArsA and ArsB proteins which contribute toward
their function as ATPase and ion transport system.  Domains of interest
in the ArsA protein are a) nucleotide binding sites, b) anion binding
sites, and c) sites of self interaction during dimerization.  The ArsB
protein will be characterized by a) purification and b) development of an
in vitro assay for 73AsO2- transport.  The ArsA and ArsB proteins form a
complex.  The methodology for reconstitution of a functional pump from
isolated ArsA and ArsB proteins will be optimized.  The stoichiometry of
the subunits in the pump will be determined, and the contact regions of
the two proteins will be identified.

The operon is metalloregulated by a diverse set of inducers, including
various salts of arsenic, antimony and bismuth.  Characterization of the
transcriptional regulators, the ArsR and ArsD proteins, will be carried
out with the following aims: a) purification of the two proteins, b)
determination of their role in regulation, including binding sites on the
proteins for DNA and ionic substrates, and c) determination of the
repressor binding sites on the DNA.

## Key facts

- **NIH application ID:** 3129207
- **Project number:** 2R01AI019793-09
- **Recipient organization:** WAYNE STATE UNIVERSITY
- **SAM.gov UEI:** M6K6NTJ2MNE5
- **Principal Investigator:** BARRY P. ROSEN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1992
- **Award amount:** $236,942
- **Award type:** 2
- **Project period:** 1987-08-01 → 1997-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3129207

## Citation

> US National Institutes of Health, RePORTER application 3129207, ATP-COUPLED ARSENICAL PUMP OF ESCHERICHIA COLI (2R01AI019793-09). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3129207. Licensed CC0.

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