113231-04-2Relevant articles and documents
Metal affinity capture tandem mass spectrometry for the selective detection of phosphopeptides
Blacken, Grady R.,Gelb, Michael H.,Turecek, Frantisek
, p. 6065 - 6073 (2006)
We report a new method called metal affinity capture that when coupled with tandem mass spectromery (MAC-MSMS) allows for the selective detection and identification of phosphopeptides in complex mixtures. Phosphopeptides are captured as ternary complexes with GaIII or FeIII and Nα,Nα-bis(carboxymethyl)lysme (LysNTA) in solution and electrosprayed as doubly or triply charged positive ions. The gas-phase complexes uniformly dissociate to produce a common (LysNTA + H) + ion that is used as a specific marker in precursor ion scans. The advantages of MAC-MSMS over the current methods of phosphopeptide detection are as follows. (1) MAC-MSMS uses metal complexes that self-assemble in solution at pH 69Ga-71Ga isotope pattern for selective recognition in mixtures. Detection by MAC-MSMS of singly and multiply phosphorylated peptides in tryptic digests is demonstrated at low-nanomolar protein concentrations.
Supramolecular self-assembly of amphiphiles on carbon nanotubes: A versatile strategy for the construction of CNT/metal nanohybrids, application to electrocatalysis
Mackiewicz, Nicolas,Surendran, Geetarani,Remita, Hynd,Keita, Bineta,Zhang, Guangjin,Nadjo, Louis,Hagege, Agnes,Doris, Eric,Mioskowski, Charles
, p. 8110 - 8111 (2008)
Homogeneous coating of carbon nanotubes with metallic nanoparticles was achieved using supramolecular auto-organization of amphiphilic molecules as template. The resulting Pd nanoparticles/carbon nanotube nanohybrids were then evaluated in electrocatalysis experiments, showing superior activity in ethanol oxidation compared to analogous systems. Copyright
Effect of N-acetylgalactosamine ligand valency on targeting dendrimers to hepatic cancer cells
Kuruvilla, Sibu P.,Tiruchinapally, Gopinath,Kaushal, Neha,ElSayed, Mohamed E.H.
, p. 27 - 36 (2018)
The display of N-acetylgalactosamine (NAcGal) ligands has shown great potential in improving the targeting of various therapeutic molecules to hepatocellular carcinoma (HCC), a severe disease whose clinical treatment is severely hindered by limitations in delivery of therapeutic cargo. We previously used the display of NAcGal on generation 5 (G5) polyamidoamine (PAMAM) dendrimers connected through a poly(ethylene glycol) (PEG) brush (i.e. G5-cPEG-NAcGal; monoGal) to effectively target hepatic cancer cells and deliver a loaded therapeutic cargo. In this study, we were interested to see if tri-valent NAcGal ligands (i.e. NAcGal3) displayed on G5 dendrimers (i.e. G5-cPEG-NAcGal3; triGal) could improve their ability to target hepatic cancer cells compared to their monoGal counterparts. We therefore synthesized a library of triGal particles, with either 2, 4, 6, 8, 11, or 14 targeting branches (i.e. cPEG-NAcGal3) attached. Conventional flow cytometry studies showed that all particle formulations can label hepatic cancer cells in a concentration-dependent manner, reaching 90–100% of cells labeled at either 285 or 570 nM G5, but interestingly, monoGal labeled more cells at lower concentrations. To elucidate the difference in internalization of monoGal versus triGal conjugates, we turned to multi-spectral imaging flow cytometry and quantified the amount of internalized (I) versus surface-bound (I0) conjugates to determine the ratio of internalization (I/I0) in all treatment groups. Results show that regardless of NAcGal valency, or the density of targeting branches, all particles achieve full internalization and diffuse localization throughout the cell (I/I0 ～ 3.0 for all particle compositions). This indicates that while tri-valent NAcGal is a promising technique for targeting nanoparticles to hepatic cancer cells, mono-valent NAcGal is more efficient, contrary to what is observed with small molecules.
Selective two-step labeling of proteins with an off/on fluorescent probe
Hirabayashi, Kazuhisa,Hanaoka, Kenjiro,Shimonishi, Manabu,Terai, Takuya,Komatsu, Toru,Ueno, Tasuku,Nagano, Tetsuo
, p. 14763 - 14771 (2011)
We present a novel design strategy for off/on fluorescent probes suitable for selective two-step labeling of proteins. To validate this strategy, we designed and synthesized an off/on fluorescent probe, 1-Ni2+, which targets a cysteine-modified hexahistidine (His) tag. The probe consists of dichlorofluorescein conjugated with nitrilotriacetic acid (NTA)-Ni2+ as the His-tag recognition site and a 2,4-dinitrophenyl ether moiety, which quenches the probe's fluorescence by photoinduced electron transfer (PeT) from the excited fluorophore to the 2,4-dinitrophenyl ether (donor-excited PeT; d-PeT) and also has reactivity with cysteine. His-tag recognition by the NTA-Ni2+ moiety is followed by removal of the 2,4-dinitrophenyl ether quencher by proximity-enhanced reaction with the cysteine residue of the modified tag; this results in a marked fluorescence increase. Addition of His-tag peptide bearing a cysteine residue to aqueous probe solution resulted in about 20-fold fluorescence increment within 10 min, which is the largest fluorescence enhancement so far obtained with a visible light-excitable fluorescent probe for a His-based peptide tag. Further, we successfully visualized CysHis6-peptide tethered to microbeads without any washing step. The probe also showed a large fluorescence increment in the presence of His6Cys-tagged enhanced blue fluorescent protein (EBFP), but not His6-tagged EBFP. We consider this system is superior to large fluorescence tags (e.g., green fluorescent protein: 27 kDa), which can perturb protein folding, trafficking and function, and also to existing small tags, which generally show little fluorescence increase upon target recognition and therefore require a washout step. This strategy should also be applicable to other tags.
The Scaffold Design of Trivalent Chelator Heads Dictates Affinity and Stability for Labeling His-tagged Proteins in vitro and in Cells
Gatterdam, Karl,Joest, Eike F.,Gatterdam, Volker,Tampé, Robert
, p. 12395 - 12399 (2018/09/18)
Small chemical/biological interaction pairs are at the forefront in tracing protein function and interaction at high signal-to-background ratios in cellular pathways. However, the optimal design of scaffold, linker, and chelator head still deserve systematic investigation to achieve the highest affinity and kinetic stability for in vitro and especially cellular applications. We report on a library of N-nitrilotriacetic acid (NTA)-based multivalent chelator heads (MCHs) built on linear, cyclic, and dendritic scaffolds and compare these with regard to their binding affinity and stability for the labeling of cellular His-tagged proteins. Furthermore, we describe a new approach for tracing cellular target proteins at picomolar probe concentrations in cells. Finally, we outline fundamental differences between the MCH scaffolds and define a cyclic trisNTA chelator that displays the highest affinity and kinetic stability of all reported reversible, low-molecular-weight interaction pairs.
METHOD FOR PREPARING PRECURSOR USED FOR LABELING HEPATOCYTE RECEPTOR AND CONTAINING TRISACCHARIDE AND DTPA LIGAND
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Paragraph 0071 - 0074, (2014/03/21)
A method for preparing a precursor used to label hepatocyte receptors is revealed. The precursor contains a bifunctional structure including trisaccharide and DTPA ligand. During synthesis processes of the precursor, silica gel columns and Reverse phase-1
