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Cone snail

Julien Echterbille, Nicolas Gilles, Romulo Araóz, Gilles Mourier, Muriel Amar, Denis Servent, Edwin De Pauw, Loic Quinton
Animal toxins are peptides that often bind with remarkable affinity and selectivity to membrane receptors such as nicotinic acetylcholine receptors (nAChRs). The latter are, for example, targeted by α-conotoxins, a family of peptide toxins produced by venomous cone snails. nAChRs are implicated in numerous physiological processes explaining why the design of new pharmacological tools and the discovery of potential innovative drugs targeting these receptor channels appear so important. This work describes a methodology developed to discover new ligands of nAChRs from complex mixtures of peptides...
February 24, 2017: Toxicon: Official Journal of the International Society on Toxinology
Stephen B Drane, Samuel D Robinson, Christopher A MacRaild, Sandeep Chhabra, Balasubramanyam Chittoor, Rodrigo A V Morales, Eleanor W W Leung, Alessia Belgi, Samuel S Espino, Baldomero M Olivera, Andrea J Robinson, David K Chalmers, Raymond S Norton
In natural proteins and peptides, amino acids exist almost invariably as l-isomers. There are, however, several examples of naturally-occurring peptides containing d-amino acids. In this study we investigated the role of a naturally-occurring d-amino acid in a small peptide identified in the transcriptome of a marine cone snail. This peptide belongs to a family of peptides known as contryphans, all of which contain a single d-amino acid residue. The solution structure of this peptide was solved by NMR, but further investigations with molecular dynamics simulations suggest that its solution behaviour may be more dynamic than suggested by the NMR ensemble...
February 17, 2017: Toxicon: Official Journal of the International Society on Toxinology
Marimuthu Vijayasarathy, Soorej M Basheer, Jayaseelan Benjamin Franklin, Padmanabhan Balaram
The occurrence of contryphans, a class of single-disulfide-bond-containing peptides, is demonstrated by the analysis of the venom of nine species of cone snails. Ten full gene sequences and two partial gene sequences coding for contryphan precursor proteins have been identified by next-generation sequencing and compared with available sequences. The occurrence of mature peptides in isolated venom has been demonstrated by LC-ESI-MS/MS analysis. De novo sequencing of reduced, alkylated contryphans from C. frigidus and C...
February 3, 2017: Journal of Proteome Research
Sue-Ann Watson, Jennifer B Fields, Philip L Munday
Ocean acidification poses a range of threats to marine invertebrates; however, the emerging and likely widespread effects of rising carbon dioxide (CO2) levels on marine invertebrate behaviour are still little understood. Here, we show that ocean acidification alters and impairs key ecological behaviours of the predatory cone snail Conus marmoreus Projected near-future seawater CO2 levels (975 µatm) increased activity in this coral reef molluscivore more than threefold (from less than 4 to more than 12 mm min(-1)) and decreased the time spent buried to less than one-third when compared with the present-day control conditions (390 µatm)...
February 2017: Biology Letters
Jason Macrander, Marymegan Daly
Sea anemones (Cnidaria, Anthozoa, and Actiniaria) use toxic peptides to incapacitate and immobilize prey and to deter potential predators. Their toxin arsenal is complex, targeting a variety of functionally important protein complexes and macromolecules involved in cellular homeostasis. Among these, actinoporins are one of the better characterized toxins; these venom proteins form a pore in cellular membranes containing sphingomyelin. We used a combined bioinformatic and phylogenetic approach to investigate how actinoporins have evolved across three superfamilies of sea anemones (Actinioidea, Metridioidea, and Actinostoloidea)...
December 8, 2016: Toxins
Enrico Leipold, Florian Ullrich, Markus Thiele, Alesia A Tietze, Heinrich Terlau, Diana Imhof, Stefan H Heinemann
The neurotoxic cone snail peptide μ-GIIIA specifically blocks skeletal muscle voltage-gated sodium (NaV1.4) channels. The related conopeptides μ-PIIIA and μ-SIIIA, however, exhibit a wider activity spectrum by also inhibiting the neuronal NaV channels NaV1.2 and NaV1.7. Here we demonstrate that those μ-conopeptides with a broader target range also antagonize select subtypes of voltage-gated potassium channels of the KV1 family: μ-PIIIA and μ-SIIIA inhibited KV1.1 and KV1.6 channels in the nanomolar range, while being inactive on subtypes KV1...
January 22, 2017: Biochemical and Biophysical Research Communications
Eline K M Lebbe, Jan Tytgat
During evolution, nature has embraced different strategies for species to survive. One strategy, applied by predators as diverse as snakes, scorpions, sea anemones and cone snails, is using venom to immobilize or kill a prey. This venom offers a unique and extensive source of chemical diversity as it is driven by the evolutionary pressure to improve prey capture and/or to protect their species. Cone snail venom is an example of the remarkable diversity in pharmacologically active small peptides that venoms can consist of...
2016: Journal of Venomous Animals and Toxins Including Tropical Diseases
Eline K M Lebbe, Maarten G K Ghequire, Steve Peigneur, Bea G Mille, Prabha Devi, Samuthirapandian Ravichandran, Etienne Waelkens, Lisette D'Souza, René De Mot, Jan Tytgat
Cone snails are predatory creatures using venom as a weapon for prey capture and defense. Since this venom is neurotoxic, the venom gland is considered as an enormous collection of pharmacologically interesting compounds having a broad spectrum of targets. As such, cone snail peptides represent an interesting treasure for drug development. Here, we report five novel peptides isolated from the venom of Conus longurionis, Conus asiaticus and Conus australis. Lo6/7a and Lo6/7b were retrieved from C. longurionis and have a cysteine framework VI/VII...
October 27, 2016: Marine Drugs
Juan E Uribe, Nicolas Puillandre, Rafael Zardoya
Understanding how the extraordinary taxonomic and ecological diversity of cone snails (Caenogastropoda: Conidae) evolved requires a statistically robust phylogenetic framework, which thus far is not available. While recent molecular phylogenies have been able to distinguish several deep lineages within the family Conidae, including the genera Profundiconus, Californiconus, Conasprella, and Conus (and within this one, several subgenera), phylogenetic relationships among these genera remain elusive. Moreover, the possibility that additional deep lineages may exist within the family is open...
October 27, 2016: Molecular Phylogenetics and Evolution
Daryl C Yang, Jennifer R Deuis, Daniel Dashevsky, James Dobson, Timothy N W Jackson, Andreas Brust, Bing Xie, Ivan Koludarov, Jordan Debono, Iwan Hendrikx, Wayne C Hodgson, Peter Josh, Amanda Nouwens, Gregory J Baillie, Timothy J C Bruxner, Paul F Alewood, Kelvin Kok Peng Lim, Nathaniel Frank, Irina Vetter, Bryan G Fry
Millions of years of evolution have fine-tuned the ability of venom peptides to rapidly incapacitate both prey and potential predators. Toxicofera reptiles are characterized by serous-secreting mandibular or maxillary glands with heightened levels of protein expression. These glands are the core anatomical components of the toxicoferan venom system, which exists in myriad points along an evolutionary continuum. Neofunctionalisation of toxins is facilitated by positive selection at functional hotspots on the ancestral protein and venom proteins have undergone dynamic diversification in helodermatid and varanid lizards as well as advanced snakes...
October 18, 2016: Toxins
Briony E Forbes
The last two years of insulin-like growth factor (IGF) research has yielded a vast literature highlighting the central role IGFs factors play in processes such as development, growth, aging and neurological function. It also provides our latest understanding of how IGF system perturbation is linked to diseases including growth deficiency, cancer, and neurological and cardiovascular diseases. A snapshot of the highlights is presented in this review, focussing on the topics of IGFs and growth, comparative and structural biology to understand insulin-like peptide function, IGFs and cancer, and IGFs and neurological function...
October 2016: Growth Hormone & IGF Research
Muriel Primon-Barros, Alexandre José Macedo
Microbial infections affect people worldwide, causing diseases with significant impact on public health, indicating the need for research and development of new antimicrobial agents. Animal venoms represent a vast and largely unexploited source of biologically active molecules with attractive candidates for the development of novel therapeutics. Venoms consist of complex mixtures of molecules, including antimicrobial peptides (AMPs). Since the discovery of AMPs, they have been studied as promising new antimicrobial drugs...
September 30, 2016: Current Topics in Medicinal Chemistry
Frédéric Ducancel
Animal venoms are complex chemical cocktails, comprising a wide range of biologically active reticulated peptides that target with high selectivity and efficacy a variety of enzymes, membrane receptors, ion channels...Venoms can therefore be seen as large natural libraries of biologically active molecules that are continuously selected and highly refined by the evolution process, up to the point where every molecule is endowed with pharmacological properties that are highly valuable in the context of human use and drug development...
2016: Biologie Aujourd'hui
John G Menting, Joanna Gajewiak, Christopher A MacRaild, Danny Hung-Chieh Chou, Maria M Disotuar, Nicholas A Smith, Charleen Miller, Judit Erchegyi, Jean E Rivier, Baldomero M Olivera, Briony E Forbes, Brian J Smith, Raymond S Norton, Helena Safavi-Hemami, Michael C Lawrence
Insulins in the venom of certain fish-hunting cone snails facilitate prey capture by rapidly inducing hypoglycemic shock. One such insulin, Conus geographus G1 (Con-Ins G1), is the smallest known insulin found in nature and lacks the C-terminal segment of the B chain that, in human insulin, mediates engagement of the insulin receptor and assembly of the hormone's hexameric storage form. Removal of this segment (residues B23-B30) in human insulin results in substantial loss of receptor affinity. Here, we found that Con-Ins G1 is monomeric, strongly binds the human insulin receptor and activates receptor signaling...
October 2016: Nature Structural & Molecular Biology
B R Green, B M Olivera
The venoms of cone snails provide a rich source of neuroactive peptides (conotoxins). Several venom peptide families have been identified that are either agonists (ι- and δ-conotoxins) or antagonists (μ- and μO-conotoxins) of voltage-gated sodium channels (VGSCs). Members of these conotoxin classes have been integral in identifying and characterizing specific neurotoxin binding sites on the channel. Furthermore, given the specificity of some of these peptides for one sodium channel subtype over another, conotoxins have also proven useful in exploring differences between VGSC subtypes...
2016: Current Topics in Membranes
Helena Safavi-Hemami, Aiping Lu, Qing Li, Alexander E Fedosov, Jason Biggs, Patrice Showers Corneli, Jon Seger, Mark Yandell, Baldomero M Olivera
A specialized insulin was recently found in the venom of a fish-hunting cone snail, Conus geographus Here we show that many worm-hunting and snail-hunting cones also express venom insulins, and that this novel gene family has diversified explosively. Cone snails express a highly conserved insulin in their nerve ring; presumably this conventional signaling insulin is finely tuned to the Conus insulin receptor, which also evolves very slowly. By contrast, the venom insulins diverge rapidly, apparently in response to biotic interactions with prey and also possibly the cones' own predators and competitors...
November 2016: Molecular Biology and Evolution
Stephen Estes, Liana Artinian, Vincent Rehder
Carbon monoxide (CO) is physiologically produced via heme degradation by heme oxygenase enzymes. Whereas CO has been identified as an important physiological signaling molecule, the roles it plays in neuronal development and regeneration are poorly understood. During these events, growth cones guide axons through a rich cellular environment to locate target cells and establish synaptic connections. Previously, we have shown that another gaseous signaling molecule, nitric oxide (NO), has potent effects on growth cone motility...
August 11, 2016: Developmental Neurobiology
Mark A Phuong, Gusti N Mahardika, Michael E Alfaro
BACKGROUND: Although diet is believed to be a major factor underlying the evolution of venom, few comparative studies examine both venom composition and diet across a radiation of venomous species. Cone snails within the family, Conidae, comprise more than 700 species of carnivorous marine snails that capture their prey by using a cocktail of venomous neurotoxins (conotoxins or conopeptides). Venom composition across species has been previously hypothesized to be shaped by (a) prey taxonomic class (i...
2016: BMC Genomics
Mohammed Abdel-Wahab, Masahiro Miyashita, Atsushi Kitanaka, Hironori Juichi, Moustafa Sarhan, Maged Fouda, Mohamed Abdel-Rahman, Samy Saber, Yoshiaki Nakagawa
Over 200 components with molecular mass ranging mainly from 400 to 4000 Da were characterized from the venom of the vermivorous cone snail Conus fulgetrum that inhabit Egyptian Red Sea. One major component having a molecular mass of 2946 Da was purified by HPLC, and its primary structure was determined by a combination of Edman degradation and MS/MS analysis.
October 2016: Bioscience, Biotechnology, and Biochemistry
Soohyun Kwon, Frank Bosmans, Quentin Kaas, Olivier Cheneval, Anne C Conibear, K Johan Rosengren, Conan K Wang, Christina I Schroeder, David J Craik
Disulfide-rich peptides isolated from cone snails are of great interest as drug leads due to their high specificity and potency toward therapeutically relevant ion channels and receptors. They commonly contain the inhibitor cystine knot (ICK) motif comprising three disulfide bonds forming a knotted core. Here we report the successful enzymatic backbone cyclization of an ICK-containing peptide κ-PVIIA, a 27-amino acid conopeptide from Conus purpurascens, using a mutated version of the bacterial transpeptidase, sortase A...
October 2016: Biotechnology and Bioengineering
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