disulfide bond problem in predicting defensin-like peptides

My sequence have 6 cysteines which are predicted to form 3 disulfide bonds. I-TASSAR can not form them well. I have already assigned contact between the disulfide-bonded residue pairs. My sequence can be :
>lamda-1
QCPDNCVNFACPGRVPYCDRDNTCQCSSWEGSGPPR

This sequence like a chimera of invertebrate defensin and vertebrate defensin owing to their cysteine pattern, whereas, between conserved cysteines, amina acids can diverge vastly.