Comparative modelling of major house dust mite allergen Der p I: structure validation using an extended environmental amino acid propensity table

Abstract

Cysteine mutagenesis for the purpose of chemical labelling was applied to the K⁺ channel neurotoxin charybdotoxin, a 37-residue peptide with six functionally essential cysteines. An additional ‘spinster cysteine’ was introduced at a position far away in space from the toxin's known interaction surface where it contacts its K⁺ channel receptor. Despite the presence of the extra unpaired cysteine residue,the toxin still folds efficiently and may be labelled by fluorescent and radioactive reagents to give a functionally competent toxin.