Research > Immunesuppressive ion channel blocking peptide toxins
The
voltage-gated Kv1.3 potassium channel plays a key role in the
activation of T lymphocytes. By blocking these channels the
proliferation of T cells can be inhibited thus suppressing T-cell
mediated immune responses, which has a great potential in the therapy
of certain autoimmune diseases. Anuroctoxin (1), a 35-amino-acid
scorpion peptide characterized previously is a high affinity blocker of
Kv1.3. Although with lower affinity, Anuroctoxin blocks Kv1.2, which is
expressed in several tissues, thus this property limits the toxin’s
potential clinical use.
In order to design new mutants of
Anuroctoxin with improved selectivity profile, a detailed understanding
of its interaction with voltage gated K+ ion channels is needed. We
have prepared synthetic version of Anuroctoxin with solid phase
synthesis and verified its activity with Kv1.2 and Kv1.3 channels. We
have determined the solution state structure of Anuroctxin using
homonuclear NMR techniques and molecular dynamics. The results obtained
from the structures based on NMR and from MD simulations suggested that
the restricted conformational space of the double substituted toxin
compared to the flexible wild-type AnTx is an important determinant of
toxin selectivity. The findings may provide foundation for the
possibility of designing additional, even more selective toxins
targeting various ion channels.
Co-laborators: Prof. Gyorgy Panyi, Channel Structure-Function Research Group at the Debrecen University, Hungary.