Biophysical Studies of a Proline-Rich Peptide from the Coral Bleach Pathogen Vibrio shiloi

Coral reef communities are an important part of the marine ecosystem. They are highly reproductive and apart from the tropical rain forest, there is no natural environment so rich in species diversity as the marine coral reef. During last two decades, there have been an increasing number of reports of disease of corals referred to as coral bleaching, which breaks the symbiotic association between the coral hosts and their photosynthetic micro algal endosymbionants known as zooxanthellae. In an attempt to reveal the actual mechanism behind coral bleaching earlier we documented that a pathogenic bacterium Vibrio shiloi was the casuative agent involved in the coral bleaching [1]. This coral pathogen (V. shiloi) produces an array of extracellular material that can inhibit photosynthesis, bleach and lyse zooxanthellae. Recently we isolated a proline-rich dodecapeptide (PYPVYAPPPVVP) from Vibrio shiloi named Toxin P and its structure and activity was confirmed by chemical synthesis [2]. The detail conformational analysis of synthetic Toxin P was carried out using CD and NMR in various media including membrane mimetic environments.