Hyp-1 protein from St John\'s wort as a PR-10 protein

Authors:

• Joanna Śliwiak,
• Zbigniew Dauter,
• Mariusz Jaskólski

Abstract

PR-10 proteins form a large subclass of plant pathogenesis-related proteins that are expressed in response to harmful environmental factors in a wide range of species. Although their function is still not clear, structural data suggest that their characteristic internal hydrophobic cavity can bind relevant plant small-molecule mediators. Hyp-1 from St John's wort ( Hypericum perforatum ), initially proposed as a catalyst for the biosynthesis of hypericin, was eventually shown to share sequence similarity and a folding pattern with PR-10 proteins. The crystal structure of Hyp-1 in complex with fluorescent probe ANS reveals three distinct and separated binding sites that are unique among PR-10 proteins. The structure can provide guidance in our quest for the true physiological ligands of Hyp-1.