Caloxin-derived peptides for the inhibition of plasma membrane calcium ATPases.

Plasma membrane calcium ATPases (PMCAs) are a family of transmembrane proteins responsible for the extrusion of cytosolic Ca to the extracellular milieu. They are important players of the calcium homeostasis possibly implicated in some important diseases. The reference inhibitors of PMCA extruding activity are on one hand ortho-vanadate (IC in the 30 mM range), and on the other a series of 12- to 20-mer peptides named caloxins (IC in the 100 µM scale).

MCH-R1 Antagonist GPS18169, a Pseudopeptide, Is a Peripheral Anti-Obesity Agent in Mice.

Melanin-concentrating hormone (MCH) is a 19 amino acid long peptide found in the brain of animals, including fishes, batrachians, and mammals. MCH is implicated in appetite and/or energy homeostasis. Antagonists at its receptor (MCH-R1) could be major tools (or ultimately drugs) to understand the mechanism of MCH action and to fight the obesity syndrome that is a worldwide societal health problem.

Fluorescent Peptide Biosensor for Probing CDK6 Kinase Activity in Lung Cancer Cell Extracts.

CDK6 kinase regulates cell-cycle progression in G1, together with CDK4, but has cell-, tissue- and developmentally distinct functions associated with transcription, angiogenesis and metabolism. Although CDK6 makes an attractive cancer biomarker and target, there are no means of assessing its activity in a complex environment. In this study, we describe the design, engineering and characterisation of a fluorescent peptide biosensor derived from 6-phosphofructokinase that reports on CDK6 kinase activity through sensitive changes in fluorescence intensity.

VHH characterization. Comparison of recombinant with chemically synthesized anti-HER2 VHH.

In the continuous exploration of the VHH chemistry, biochemistry and therapeutic future use, we investigated two different production strategies of this small antibody-like protein, using an anti-HER2 VHH as a model. The total chemical synthesis of the 125 amino-acid peptide was performed with reasonable yield, even if optimization will be necessary to upgrade this kind of production. In parallel, we expressed the same sequence in two different hosts: Escherichia coli and Pichia pastoris.

Screening ubiquitin specific protease activities using chemically synthesized ubiquitin and ubiquitinated peptides.

Ubiquitin, a 76 amino acid protein, is a key component that contributes to cellular protein homeostasis. The specificity of this modification is due to a series of enzymes: ligases, attaching the ubiquitin to a lysine, and deubiquitinases, which remove it. More than a hundred of such proteins are implicated in the regulation of protein turnover.

Total chemical synthesis, refolding, and crystallographic structure of fully active immunophilin calstabin 2 (FKBP12.6).

Synthetic biology (or chemical biology) is a growing field to which the chemical synthesis of proteins, particularly enzymes, makes a fundamental contribution. However, the chemical synthesis of catalytically active proteins (enzymes) remains poorly documented because it is difficult to obtain enough material for biochemical experiments. We chose calstabin, a 107-amino-acid proline isomerase, as a model.

The novel nonapeptide acein targets angiotensin converting enzyme in the brain and induces dopamine release.

Background And Purpose: Using an in-house bioinformatics programme, we identified and synthesized a novel nonapeptide, H-Pro-Pro-Thr-Thr-Thr-Lys-Phe-Ala-Ala-OH. Here, we have studied its biological activity, in vitro and in vivo, and have identified its target in the brain.

Experimental Approach: The affinity of the peptide was characterized using purified whole brain and striatal membranes from guinea pigs and rats .

Heating and microwave assisted SPPS of C-terminal acid peptides on trityl resin: the truth behind the yield.

Despite correct purity of crude peptides prepared on trityl resin by Fmoc/tBu microwave assisted solid phase peptide synthesis, surprisingly, lower yields than those expected were obtained while preparing C-terminal acid peptides. This could be explained by cyclization/cleavage through diketopiperazine formation during the second amino acid deprotection and third amino acid coupling. However, we provide here evidence that this is not the case and that this yield loss was due to high temperature promoted hydrolysis of the 2-chlorotrityl ester, yielding premature cleavage of the C-terminal acid peptides.

Microwave-mediated reduction of disulfide bridges with supported (tris(2-carboxyethyl)phosphine) as resin-bound reducing agent.

We report on the synthesis and use of a new supported reagent consisting in tris(2-carboxyethyl)phosphine (TCEP) immobilized on hydrophilic PEG based resin beads. Used in conjunction with a 5 min microwave (MW) irradiation, "supported TCEP" reduced disulfide bridges in free thiols in peptides having two or more cysteine residues. Separation of reaction products from reducing agent was easily performed by simple filtration.

Supported oligomethionine sulfoxide and Ellman's reagent for cysteine bridges formation.

A large number of bioactive peptides are cyclized through a disulfide bridge. This structural feature is very important for both bioactivity and stability. The oxidation of cysteine side chains is challenging not only to avoid intermolecular reaction leading to oligomers and oxidation of other residues but also to remove solvents and oxidant such as dimethyl sulfoxide.

Oxyfold: a simple and efficient solid-supported reagent for disulfide bond formation.

The synthesis and use of novel polymer-supported reagents for disulfide bond formation is described. This family of supported reagents consists of a series of oxidized methionines grafted onto a solid support. Their cost and the simplicity of their preparation through N-carboxyanhydride polymerization on beads make them reactants of choice for the formation of disulfide bridges in peptides.

A multiplex assay for the simultaneous detection of antibodies against 15 Plasmodium falciparum and Anopheles gambiae saliva antigens.

Background: Assessment exposure and immunity to malaria is an important step in the fight against the disease. Increased malaria infection in non-immune travellers under anti-malarial chemoprophylaxis, as well as the implementation of malaria elimination programmes in endemic countries, raises new issues that pertain to these processes. Notably, monitoring malaria immunity has become more difficult in individuals showing low antibody (Ab) responses or taking medications against the Plasmodium falciparum blood stages.

Bioinformatics-based discovery and identification of new biologically active peptides for GPCR deorphanization.

Owing to their involvement in many physiological and pathological processes, G-protein-coupled receptors (GPCRs) are interesting targets for drug development. Approximately, 100 endoGPCRs lack their natural ligands and remain orphan (oGPCRs). Consequently, oGPCR deorphanization appears a promising research field for the development of new therapeutics.