https://doi.org/10.15255/KUI.2003.034
Published: Kem. Ind. 53 (7-8) (2004) 333–338
Paper reference number: KUI-34/2003
Paper type: Original scientific paper
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Evaluation of the Impact of Proline on the Folding of α-Conotoxins

A. K. Croskey and B. Hargittai

Abstract

Department of Chemistry, Mathematics and Physical Sciences, Saint Francis University, Loretto, Pennsylvania 15940, USA Evaluation of the role of disulfide bridges is essential in our understanding of protein folding. Our research group is interested in exploring how slight changes in the sequences of small peptides affect their folding properties. The compounds under consideration were multiple disulfide bridge- containing peptides belonging to the class of α-conotoxins, α-conotoxins GI, GII (found in Conus Geographus), SI, SIA (found in Conus Striatus), and MI (found in Conus Magus), and their analogs. These are all thirteen or fourteen amino acid-containing peptide amides having four cysteine residues. The four cysteine residues can form two disulfide bridges, leading to three possible regioisomers. The amino acid in position 9 of these peptides plays an important role in the biological characteristics of these compounds. In our studies we have investigated the effects of different amino acids, primarily proline, in this position on the folding of the peptides. Our results indicate that proline’s cyclic nature may impose steric constraints for the folding of α-conotoxins.

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Keywords

α-conotoxins, folding, disulfide-paired regioisomers