A new study published in the Proceedings of the National Academy of Sciences USA, PNAS, conducted by researchers at the Ruhr University in Bochum, shows how peptides can be designed so that attack bacterial cells.

Researchers believe that the disposal of pathogenic bacteria could be done without harming human cells.

Moreover, this type of therapy would reduce the risk of resistance that developed most pathogens to previously applied drugs.

Previous studies have already shown that many antimicrobial peptides interact with cell membranes of the bacteria and thus perform its microbicidal effect.

RUB team has turned his attention to the study of a peptide called MP196, which is a group of very small positively charged peptides consisting of four to ten amino acids.

From previous studies it is known that the MP196 can cope with a variety of bacteria including some that are multi - drug-resistant, but it is unclear exactly how this process is carried out.

Researchers have demonstrated that prevents MP196 proteins in the cell membrane of the bacteria and thereby distort two key cellular processes: cell wall biosynthesis and cell breathing.

Through disruption of cell wall biosynthesis, the peptide interferes with the integrity of the bacterial cell, and by interfering with the cellular respiration, distorts the production of ATP, the molecule that stores the energy used by the cell.

Scientists are confident that the MP196 offers a starting point for developing new drugs that attack specific classes of bacteria without harming human cells, but to be confirmed in their findings need to go a long way.

The study is part of the development of innovative antibiotics.

To solve new drugs, federal authorities need detailed information about the procedure and the effects of drugs on both pathogens and on human cells.

Caspase-3 Assay for Apoptosis Detection in Whole, Living Cells 
Catalog no. 9125 (25-50 tests)

Apoptosis is an evolutionarily conserved form of cell suicide mediated by a cascade of proteolytic enzymes called caspases. Pro-apoptotic signals activate the enzymatic cascade resulting in the cleavage of protein substrates, leading to the disassembly of the cell. Caspases have been identified in organisms ranging fromC. eleganstoMembers of the mammalian caspase family of cysteinyl aspartate-specific proteases play distinct roles in apoptosis and inflammation.

Caspases
Active caspase enzymes exhibit catalytic and substrate specificities comprised of short tetra-peptide amino acid sequences that must contain an aspartate in the P1 position. These preferred tetra-peptide sequences have been used to derive peptides that specifically compete for caspase binding. In addition to the distinctive aspartate cleavage site at P1, the catalytic domains of the caspases typically require four amino acids to the left of the cleavage site with P4 as the prominent specificity-determining residue. Addition of a fluoromethyl ketone (FMK) to the tetrapeptide results in an irreversible linkage and permanent inactivation of the cysteine protease enzyme. Furthermore, conjugation of a fluorescent moiety at the amino terminus yields a probe that allows for the detection of caspase activity.

FLICA® 660 Caspase-3 Assay: Detection Mechanism

The far-red FLICA® 660-DEVD-FMK caspase-3 detection probe is comprised of the preferred affinity peptide sequence (DEVD) targeted by activated caspase-3 and caspase-7, a far-red fluorescent 660 dye label, and a fluoromethyl ketone (FMK) reactive moiety. The resulting fluorescent caspase-3 inhibitor probe forms an irreversible, covalent bond with active caspase-3 enzymes, efficiently labeling the target for detection. Due to its cell permeant nature and fluorescence properties, the far-red FLICA caspase-3 detection probe enables whole cell analysis via common fluorescence detection methods.

To use FLICA Caspase-3 Assay, add the caspase-3 detection probe directly to suspension cell or tissue culture media, incubate, and wash. The cell permeant, far-red FLICA caspase-3 detection probe will efficiently diffuse into cells and irreversibly bind to activated caspase-3 enzymes, thereby retaining the red signal inside caspase-3-positive cells. Cells not bearing active caspase-3 return to a non-fluorescent status after the wash step.

The FLICA® 660 caspase-3 detection probe has an optimal excitation at 660 nm and optimal emission range from 680-690 nm. As such, it has demonstrated excellent excitation efficiency with a conventional red HeNe laser with a 633 nm excitation, enabling samples to be analyzed with most flow cytometers and fluorescence microscopes equipped with electronic grey scale image capabilities. Cells labeled with the FLICA® caspase-3 detection probe may be read immediately or preserved for 16 hours using the fixative.

Cat #: 9125 (25-50 tests)

Price: 250 Euro (without VAT)

ADWX-1 is an optimised synthetic analog of the scorpion peptide BmKTx. ADWX-1 is known to block voltage-gated K_v1.3 channel with a high affinity (IC₅₀ = 1.89 pM) and selectivity (340 fold greater affinity than for voltage-dependent ).ADWX-1 inhibits CD4⁺ CCR7^- T-cell proliferation. ADWX-1 is an interesting therapeutic candidate to treat auto-immune disorders such as multiple sclerosis, type-1 diabetes, rheumatoid arthritis and psoriasis. This peptide is a valuable tool for studying the structure-function of K_v1.3 channel and auto-immunity pathways.

Product Specifications

AA sequence: Val-Gly-Ile-Asn-Val-Lys-Cys⁷-Lys-His-Ser-Arg-Gln-Cys¹³-Leu-Lys-Pro-Cys¹⁷-Lys-Asp-Ala-Gly-Met-Arg-Phe-Gly-Lys-Cys²⁷-Thr-Asn-Gly-Lys-Cys³²-His-Cys³⁴-Thr-Pro-Lys-OH
Disulfide bonds between: Cys⁷-Cys²⁷, Cys¹³-Cys³², Cys¹⁷-Cys³⁴
Length (aa): 37
Formula: C₁₆₉H₂₈₁N₅₇O₄₆S₇ 
Molecular Weight: 4071.90 Da 
Purity rate: > 98%
Appearance: White lyophilized solid
Solubility: water and saline buffer
CAS number: not available
Source: Synthetic

Catalog N° 13ADW001

GaTx1: Toxin Properties

The GaTx1 peptide was originally isolated from the venom of Leiurus quinquestriatus hebraeus. This peptide is a potent and selective inhibitor of CFTR, an anion selective channel belonging to the ABC transporter superfamily. It was shown to block CFTR channels in a state dependent manner by acting from the internal face of the channel and it is supposed to be a non competitive inhibitor of ATP-dependent channel gating. GaTx1 is a valuable tool to explore the function of CFTR.

Product Specifications

AA sequence: Cys¹-Gly-Pro-Cys⁴-Phe-Thr-Thr-Asp-His-Gln-Met-Glu-Gln-Lys-Cys¹⁵-Ala-Glu-Cys¹⁸-Cys¹⁹-Gly-Gly-Ile-Gly-Lys-Cys²⁵-Tyr-Gly-Pro-Gln-Cys³⁰-Leu-Cys³²-Asn-Arg-NH₂
Disulfide bonds between: Cys¹-Cys¹⁸, Cys⁴-Cys²⁵, Cys¹⁵-Cys³⁰, and Cys¹⁹-Cys³²
Length (aa): 34
Formula: C₁₄₇H₂₂₄N₄₆O₄₇S₉₆ 
Molecular Weight: 3674.2 Da
Appearance: White lyophilized solid
Solubility: water and saline buffer
CAS number: not available
Source: Synthetic

Catalog N: 13GTX001

Obtustatin: Toxin Properties

Obtustatin is a 41 amino acid disintegrin peptide isolated from the venom of the Vipera lebetina obtusa. It is a potent (IC₅₀ = 2 nM) and selective inhibitor of the binding of α₁β₁ integrin to collagen IV.  Contrary to other known disintegrins, it does not contain the classical RGD sequence. Does not show inhibitory activity toward other integrins, including α₂β₁, α_IIbβ₃, α_vβ₃, α₄β₁, α₅β₁, α₆β₁, and α₉β₁, α₄β₇ integrins. Obtustatin potently inhibits angiogenesis in chicken and in mouse model and reduces tumor development by half.

Product Specifications

AA sequence: Cys¹-Thr-Thr-Gly-Pro-Cys⁶-Cys⁷-Arg-Gln-Cys¹⁰-Lys-Leu-Lys-Pro-Ala-Gly-Thr-Thr-Cys¹⁹-Trp-Lys-Thr-Ser-Leu-Thr-Ser-His-Tyr-Cys²⁹-Thr-Gly-Lys-Ser-Cys³⁴-Asp-Cys³⁶-Pro-Leu-Tyr-Pro-Gly-OH
(Disulfide bonds between Cys¹-Cys¹⁰, Cys⁶-Cys²⁹, Cys⁷-Cys³⁴ and Cys¹⁹-Cys³⁶)
Length (aa): 41
Formula: C₁₈₄H₂₈₄N₅₂O₅₇S₈
Molecular Weight: 4393.13 Da
Appearance: White lyophilized solid
Solubility: aqueous buffer
CAS number: not available
Source: Synthetic
Purity rate: > 97 %

Catalog N: 10OBT001