Multigene Family of Pore-Forming Toxins from Sea Anemone Heteractis crispa

Abstract

Sea anemones produce pore-forming toxins, actinoporins, which are interesting as tools for cytoplasmic membranes study, as well as being potential therapeutic agents for cancer therapy. This investigation is devoted to structural and functional study of the Heteractis crispa actinoporins diversity. Here, we described a multigene family consisting of 47 representatives expressed in the sea anemone tentacles as prepropeptide-coding transcripts. The phylogenetic analysis revealed that actinoporin clustering is consistent with the division of sea anemones into superfamilies and families. The transcriptomes of both H. crispa and Heteractis magnifica appear to contain a large repertoire of similar genes representing a rapid expansion of the actinoporin family due to gene duplication and sequence divergence. The presence of the most abundant specific group of actinoporins in H. crispa is the major difference between these species. The functional analysis of six recombinant actinoporins revealed that H. crispa actinoporin grouping was consistent with the different hemolytic activity of their representatives. According to molecular modeling data, we assume that the direction of the N-terminal dipole moment tightly reflects the actinoporins’ ability to possess hemolytic activity.

A new multigene HCIQ subfamily from the sea anemone Heteractis crispa encodes Kunitz-peptides exhibiting neuroprotective activity against 6-hydroxydopamine

“…The HCGN group was represented by only one sequence with propeptide insertion. The pro-part contained the subtilisin/kexin-like endoproteinase cleavage site (Lys-Arg) also found in precursors of actinoporins [32][33][34] and neurotoxins [35][36][37] involved in sea anemone venoms. www.nature.com/scientificreports www.nature.com/scientificreports/ Obviously, the mature HCIQ sequences start with Ile-Gln-(IQ-), rather than with Gly-Asn-(GN-) as suggested earlier, so, we designated the peptides as HCIQ where "HC" means H. crispa (Fig.…”

Magnificamide, a β-Defensin-Like Peptide from the Mucus of the Sea Anemone Heteractis magnifica, Is a Strong Inhibitor of Mammalian α-Amylases

“…Sea anemones are ancient sessile predators inhabiting the marine environment. They have specialized stinging cells which contain venom rich in peptides acting on different biological targets, mainly cytoplasmic membranes [36,37,38] and ion channels [39,40,41,42,43,44]. Venom with such a complex composition ensured the existence of sea anemones for millions of years [45].…”

Sea Anemone Toxins: A Structural Overview

“…Type II cytolysins appear as multigene families [57,58], resulting in many protein isoforms with variable levels of sequence identity (60–80%). Interestingly, these sequence differences are sufficient to cause large differences in solubility as well as hemolytic [59] and general cytolytic [60] activity, which suggests that they may target a wide range of tissues, organisms, or even play several ecological roles.…”