Oral Presentation International Peptide Symposium 2023

Structural analysis of an Asterias rubens peptide indicates the presence of a disulfide directed β-hairpin (#40)

Rozita Takjoo 1 , Casey Schmidt 1 , David Wilson 1 , Naeem Shaikh 2 , Kartik Sunagar 2 , Alex Loukas 1 , Michael Smout 1 , Norelle Daly 1
  1. James Cook University, Cairns, QLD, Australia
  2. Indian Institute of Science, Bangalore, India

 

Sea stars are an abundant group of marine invertebrates that display remarkably robust regenerative capabilities throughout all life stages. Numerous proteins and peptides have been identified in a proteome study on the coelomic fluid (biofluid) of the common sea star Asterias rubens, which appear to be involved with the wound-healing response. However, the three-dimensional structure and function of several of these injury-responsive peptides has yet to be investigated, including the 28-residue peptide KASH2. Here we show this peptide adopts a disulfide-directed β-hairpin fold (DDH). The DDH motif appears to be evolutionarily related to the inhibitor cystine knot motif, which is one of the most widespread disulfide-rich peptide folds. The DDH motif was originally thought to be restricted to arachnids, but our study suggests that it could have originated in sea stars as a result of convergent evolution. The widely conserved DDH fold has potential cross-phyla wound healing capacity, but we showed that KASH2 does not enhance the proliferation of human fibroblasts, a simple method for wound healing re-epithelialisation screening. Therefore, additional research is necessary to determine the role of KASH2 in the sea stars.