STRUCTURE-FUNCTIONAL CHARACTERIZATION OF ARGIOPINE - AN ION CHANNEL BLOCKER FROM THE VENOM OF SPIDER ARGIOPE-LOBATA

Abstract

Argiopine, a compound capable of blocking the glutamate-activated ion channels in experiments with glutamatergic synapses of blowfly larvae, was isolated from the venom of spider Argiope lobata. Argiopine-receptor complex has KD 6,7 .cntdot. 10-7 M. The venom solution was treated with 60% ethanol, centrifuged and supernatant was subjected to reversed-phase HPLC in the acetonitrile concentration gradient. Argiopine structure was established using 1H- and 13C-NMR spectroscopy, mass spectrometry, elemental and amino acid analysis. Argiopine (molecular mass 636) consists of arginine (free .alpha.-NH2) linke with polyamine.sbd.NH(CH2)3NH(CH2)3NH(CH2)5NH-through a peptide bond. The polyamine is connected to the .alpha.-carboxyl group of asparagine whose .alpha.-amino group is linked to 2,4-dihydroxyphenylacetic acid.