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Ph.D., Harvard University
Professor of Medical Science and chairman
Department of Molecular Pharmacology, Physiology and Biotechnology
487 Biomedical Center
Tel: (401) 863-1596
Email: Edward_Hawrot@Brown.edu
Go to lab web page
The nicotinic acetylcholine receptor (nAChR) mediates synaptic transmission
at the neuromuscular junction, in peripheral autonomic ganglia, and in the
central nervous system. The nAChR belongs to a super-family of ligand-gated
channels which include the glycine and GABA-A receptors. In the case of the
nAChR, receptor activation occurs after binding of the physiological agonist,
acetylcholine (ACh), to the receptor complex leading to the transient formation
of a cation-selective channel. Antagonists with relative specificity for
the nAChR include tubocurarine and the snake venom-derived neurotoxins such
as alpha-bungarotoxin (BGTX) and alpha-cobratoxin. Our major interest is
in determining the molecular and structural basis for the specificity of
drug-receptor interactions. To accomplish this we are carrying out protein
and peptide biophysical studies of receptor fragments. These studies include
determining the solution structure of toxin-receptor fragment complexes using
modern multidimensional NMR spectroscopic techniques. We also are applying
molecular biological approaches to this problem by using heterologous expression
and site-directed mutagenesis of both receptor and toxin residues in order
to elucidate the structure-function relationship in this system. Both approaches
are complementary and will facilitate the complete structural determination
of the ligand binding site in the nicotinic acetylcholine receptor. Such
information could provide the basis for the rational design of drugs selective
for such sites.
Zeng, H., Moise, L.,. Grant, M.A., and Hawrot, E. The Solution Structure
of the Complex Formed between alpha-Bungarotoxin and an 18mer Cognate Peptide
Derived from the alpha1 Subunit of the Nicotinic Acetylcholine Receptor from
Torpedo californica. Journal of Biological Chemistry, 276: 22930-22940, 2001.
Spura, A., Riel, R., Freedman, N.D., Agrawal, S., Seto, C., & Hawrot,
E. (2000) Biotinylation of substituted cysteines in the nicotinic acetylcholine
receptor reveals distinct binding modes for alpha-bungarotoxin and Erabutoxin
a. Journal of Biological Chemistry 275: 22452-22460. (http://www.jbc.org/cgi/content/full/275/29/22452)
Levandoski, M.M., Caffery, P., Rogowski, R.S., Shi, Q.-L., & Hawrot,
E. (2000) Recombinant expression of alpha-bungarotoxin in Pichia pastoris
facilitates identification of mutant toxins engineered to recognize neuronal
nicotinic acetylcholine receptors. The Journal of Neurochemistry, 74: 1279-1289.
Blein, S., Hawrot, E., & Barlow, P. (2000) The metabotropic GABA receptor:
molecular insights and their functional consequences. Cell and Molecular
Life Science, 57: 635-650.
Spura, A., Russin, T.S., Freedman, N., Grant, M., McLaughlin, J.T., & Hawrot,
E. (1999) Probing the agonist domain of the nicotinic acetylcholine receptor
by cysteine scanning mutagenesis reveals residues in proximity to the alpha-bungarotoxin
binding site. Biochemistry 38: 4912-4921.
Rosenthal, J.A., Levandoski, M.M., Chang, B., Potts, J.F., Shi, Q.-L., and
Hawrot, E. (1999) The functional role of positively charged amino acid side
chains in alpha-bungarotoxin revealed by site-directed mutagenesis of a His-tagged
recombinant alpha-bungarotoxin. Biochemistry 38: 7847-7855.
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