Neutralization of Myotoxin II, a Phospholipase A Homologue from Venom, Using Peptides Discovered via Phage Display Technology.

Many snake venom toxins cause local tissue damage in prey and victims, which constitutes an important pathology that is challenging to treat with existing antivenoms. One of the notorious toxins that causes such effects is myotoxin II present in the venom of the Central and Northern South American viper, . This Lys49 PLA homologue is devoid of enzymatic activity and causes myotoxicity by disrupting the cell membranes of muscle tissue.

Peptide Inhibitors of the α-Cobratoxin-Nicotinic Acetylcholine Receptor Interaction.

Venomous snakebites cause >100 000 deaths every year, in many cases via potent depression of human neuromuscular signaling by snake α-neurotoxins. Emergency therapy still relies on antibody-based antivenom, hampered by poor access, frequent adverse reactions, and cumbersome production/purification. Combining high-throughput discovery and subsequent structure-function characterization, we present simple peptides that bind α-cobratoxin (α-Cbtx) and prevent its inhibition of nicotinic acetylcholine receptors (nAChRs) as a lead for the development of alternative antivenoms.

Pitfalls to avoid when using phage display for snake toxins.

Antivenoms against bites and stings from snakes, spiders, and scorpions are associated with immunological side effects and high cost of production, since these therapies are still derived from the serum of hyper-immunized production animals. Biotechnological innovations within envenoming therapies are thus warranted, and phage display technology may be a promising avenue for bringing antivenoms into the modern era of biologics. Although phage display technology represents a robust and high-throughput approach for the discovery of antibody-based antitoxins, several pitfalls may present themselves when animal toxins are used as targets for phage display selection.

From Fangs to Pharmacology: The Future of Snakebite Envenoming Therapy.

The snake is the symbol of medicine due to its association with Asclepius, the Greek God of medicine, and so with good reasons. More than 725 species of venomous snakes have toxins specifically evolved to exert potent bioactivity in prey or victims, and snakebites constitute a public health hazard of high impact in Asia, Africa, Latin America, and parts of Oceania. Parenteral administration of antivenoms is the mainstay in snakebite envenoming therapy.

Synthesis and Characterisation of Substrate-Based Peptides as Inhibitors of Histone Demethylase KDM4C.

The design and synthesis of modified pentapeptides based on a truncated version of the substrate for KDM4C, a histone lysine demethylase (KDM), and investigation of their inhibitory activity at KDM4C is reported. By modifying the lysine residue corresponding to lysine 9 at histone 3 (H3K9), three different series of peptides were designed and synthesized. One series contained N-acylated H3K9 and two series introduced triazoles in this position via click chemistry to enable facile variation of headgroups.

Danger in the reef: Proteome, toxicity, and neutralization of the venom of the olive sea snake, Aipysurus laevis.

Four specimens of the olive sea snake, Aipysurus laevis, were collected off the coast of Western Australia, and the venom proteome was characterized and quantitatively estimated by RP-HPLC, SDS-PAGE, and MALDI-TOF-TOF analyses. A. laevis venom is remarkably simple and consists of phospholipases A2 (71.

Snake venomics of monocled cobra (Naja kaouthia) and investigation of human IgG response against venom toxins.

The venom proteome of the monocled cobra, Naja kaouthia, from Thailand, was characterized by RP-HPLC, SDS-PAGE, and MALDI-TOF-TOF analyses, yielding 38 different proteins that were either identified or assigned to families. Estimation of relative protein abundances revealed that venom is dominated by three-finger toxins (77.5%; including 24.

A fluorescence resonance energy transfer-based method for histone methyltransferases.

A simple dye-quencher fluorescence resonance energy transfer (FRET)-based assay for methyltransferases was developed and used to determine kinetic parameters and inhibitory activity at EHMT1 and EHMT2. Peptides mimicking the truncated histone H3 tail were functionalized in each end with a dye and a quencher, respectively. When lysine-9 residues in the peptides were methylated, they were protected from cleavage by endoproteinase-EndoLysC, whereas unmethylated peptides were cleaved, resulting in an increase in fluorescent intensity.

Unveiling the nature of black mamba (Dendroaspis polylepis) venom through venomics and antivenom immunoprofiling: Identification of key toxin targets for antivenom development.

Unlabelled: The venom proteome of the black mamba, Dendroaspis polylepis, from Eastern Africa, was, for the first time, characterized. Forty- different proteins and one nucleoside were identified or assigned to protein families. The most abundant proteins were Kunitz-type proteinase inhibitors, which include the unique mamba venom components 'dendrotoxins', and α-neurotoxins and other representatives of the three-finger toxin family.

Dissecting the binding mode of low affinity phage display peptide ligands to protein targets by hydrogen/deuterium exchange coupled to mass spectrometry.

Phage display (PD) is frequently used to discover peptides capable of binding to biological protein targets. The structural characterization of peptide-protein complexes is often challenging due to their low binding affinities and high structural flexibility. Here, we investigate the use of hydrogen/deuterium exchange mass spectrometry (HDX-MS) to characterize interactions of low affinity peptides with their cognate protein targets.

Substrate- and cofactor-independent inhibition of histone demethylase KDM4C.

Inhibition of histone demethylases has within recent years advanced into a new strategy for treating cancer and other diseases. Targeting specific histone demethylases can be challenging, as the active sites of KDM1A-B and KDM4A-D histone demethylases are highly conserved. Most inhibitors developed up-to-date target either the cofactor- or substrate-binding sites of these enzymes, resulting in a lack of selectivity and off-target effects.

Analogues of the Natural Product Sinefungin as Inhibitors of EHMT1 and EHMT2.

A series of analogues of the natural product sinefungin lacking the amino acid moiety was synthesized and probed for their ability to inhibit EHMT1 and EHMT2. This study led to inhibitors 3b and 4d of methyltransferase activity of EHMT1 and EHMT2 and it demonstrates that such analogues constitute an interesting scaffold to develop selective methyltransferase inhibitors. Surprisingly, the inhibition was not competitive toward AdoMet.

Posttranslational modifications of the histone 3 tail and their impact on the activity of histone lysine demethylases in vitro.

Posttranslational modifications (PTMs) of the histone H3 tail such as methylation, acetylation and phosphorylation play important roles in epigenetic signaling. Here we study the effect of some of these PTMs on the demethylation rates of methylated lysine 9 in vitro using peptide substrates mimicking histone H3. Various combinations with other PTMs were employed to study possible cross-talk effects by comparing enzyme kinetic characteristics.

Inhibitor scaffold for the histone lysine demethylase KDM4C (JMJD2C).

The human histone demethylases of the KDM4 (JMJD2) family have been associated to diseases such as prostate and breast cancer, as well as X-linked mental retardation. Therefore, these enzymes are considered oncogenes and their selective inhibition might be a possible therapeutic approach to treat cancer. Here we describe a heterocyclic ring system library screened against the histone demethylase KDM4C (JMJD2C) in the search for novel inhibitory scaffolds.

Inhibitors of histone demethylases.

Methylated lysines are important epigenetic marks. The enzymes involved in demethylation have recently been discovered and found to be involved in cancer development and progression. Despite the relative recent discovery of these enzymes a number of inhibitors have already appeared.

Encapsulation efficiency measured on single small unilamellar vesicles.

In this communication we present a fluorescent based method to measure the encapsulation efficiency in single small unilamellar vesicles. The single small unilamellar vesicles are loaded with a dye in the membrane and a dye in the lumen. They are immobilized on a surface and then imaged with a fluorescent microscope.

Photodimerization in pyrimidine-substituted dipeptides.

Ten N(epsilon)-glycylornithineamide derivatives have been synthesized containing various N(alpha)-linked pyrimidine-1-ylacetyl groups which can undergo (2pi + 2pi) photodimerization on irradiation with UV light at 254 nm. The dimerization efficiency of the free and bound pyrimidine groups was compared in aqueous solution: it was dependent on the substitution of the pyrimidine ring. N(alpha),N(alpha')-bis-(uracil-1-ylacetyl)-(N(epsilon)-glycylornithineamide) and N(alpha),N(alpha')-bis-(5-bromouracil-1-ylacetyl)-(N(epsilon)-glycylornithineamide) were identified as possible candidates for optical data storage.