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Find video protocols related to scientific articles indexed in Pubmed.
Investigation of the protein alkylation sites of the STAT3:STAT3 inhibitor Stattic by mass spectrometry.
Bioorg. Med. Chem. Lett.
PUBLISHED: 03-26-2013
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STAT3 (Signal Transducer and Activator of Transcription factor 3) is constitutively active in a wide range of human tumours. Stattic is one of the first non-peptidic small molecules reported to inhibit formation of the STAT3:STAT3 protein dimer complex. A mass spectrometry method has been developed to investigate the binding of Stattic to the un-phosphorylated STAT3?tc (U-STAT3) protein. Alkylation of four cysteine residues has been observed with possible reaction at a fifth which could account for the mechanism of action.
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Observation of unphosphorylated STAT3 core protein binding to target dsDNA by PEMSA and X-ray crystallography.
FEBS Lett.
PUBLISHED: 01-17-2013
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The STAT3 transcription factor plays a central role in a wide range of cancer types where it is over-expressed. Previously, phosphorylation of this protein was thought to be a prerequisite for direct binding to DNA. However, we have now shown complete binding of a purified unphosphorylated STAT3 (uSTAT3) core directly to M67 DNA, the high affinity STAT3 target DNA sequence, by a protein electrophoretic mobility shift assay (PEMSA). Binding to M67 DNA was inhibited by addition of increasing concentrations of a phosphotyrosyl peptide. X-ray crystallography demonstrates one mode of binding that is similar to that known for the STAT3 core phosphorylated at Y705.
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Facile nucleophilic substitution at the C3a tertiary carbon of the 3a-bromohexahydropyrrolo[2,3-b]indole scaffold.
Org. Biomol. Chem.
PUBLISHED: 09-20-2010
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The synthesis of 3a-substituted hexahydropyrrolo[2,3-b]indole derivatives via nucleophilic substitution at the C3a position is reported. Nitrogen-, oxygen-, sulfur-, fluoro- and carbon-based nucleophiles have been employed, using both conventional organic solvents and ionic liquids. The C3a-substituted derivatives were obtained in good to excellent yields.
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A novel small-molecule inhibitor of IL-6 signalling.
Bioorg. Med. Chem. Lett.
PUBLISHED: 08-11-2010
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A small library of pyrrolidinesulphonylaryl molecules has been synthesized via an efficient 4-step route, and members evaluated for their ability to inhibit IL-6 signalling. One molecule (6a) was found to have promising activity against IL-6/STAT3 signalling at the low micromolar level, and to selectively inhibit phosphorylation of STAT3 (but not STAT1) in IL-6 stimulated MDA-MB-231 breast cancer and HeLa cell lines. It was also selectively cytostatic in MDA-MB-231 (STAT3-dependent) versus A4 (STAT3-null) cells suggesting STAT3-specific inhibitory properties.
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Facile oxidation of electron-poor benzo[b]thiophenes to the corresponding sulfones with an aqueous solution of H2O2 and P2O5.
Chem. Commun. (Camb.)
PUBLISHED: 01-25-2010
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A facile oxidation for the clean conversion of benzo[b]thiophenes to their corresponding sulfones is described employing an aqueous solution of H(2)O(2) and P(2)O(5); the solution can be prepared and stored on a multi-gram scale with a shelf-life of up to two weeks.
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Targeting protein-protein interactions for therapeutic intervention: a challenge for the future.
Future Med Chem
PUBLISHED: 04-01-2009
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Over the last two decades, an increasing research effort in academia and industry has focused on the modulation (both inhibition and stabilization) of protein-protein interactions (PPIs) in order to develop novel therapeutic approaches and target-selective agents in drug discovery.
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Small-molecule inhibition of c-MYC:MAX leucine zipper formation is revealed by ion mobility mass spectrometry.
J. Am. Chem. Soc.
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The leucine zipper interaction between MAX and c-MYC has been studied using mass spectrometry and drift time ion mobility mass spectrometry (DT IM-MS) in addition to circular dichroism spectroscopy. Peptides comprising the leucine zipper sequence with (c-MYC-Zip residues 402-434) and without a postulated small-molecule binding region (c-MYC-Zip?DT residues 406-434) have been synthesized, along with the corresponding MAX leucine zipper (MAX-Zip residues 74-102). c-MYC-Zip:MAX-Zip complexes are observed both in the absence and in the presence of the reported small-molecule inhibitor 10058-F4 for both forms of c-MYC-Zip. DT IM-MS, in combination with molecular dynamics (MD), shows that the c-MYC-Zip:MAX-Zip complex [M+5H](5+) exists in two conformations, one extended with a collision cross section (CCS) of 1164 ± 9.3 Å(2) and one compact with a CCS of 982 ± 6.6 Å(2); similar values are observed for the two forms of c-MYC-Zip?DT:MAX-Zip. Candidate geometries for the complexes have been evaluated with MD simulations. The helical leucine zipper structure previously determined from NMR measurements (Lavigne, P.; et al. J. Mol. Biol. 1998, 281, 165), altered to include the DT region and subjected to a gas-phase minimization, yields a CCS of 1247 Å(2), which agrees with the extended conformation we observe experimentally. More extensive MD simulations provide compact complexes which are found to be highly disordered, with CCSs that correspond to the compact form from experiment. In the presence of the ligand, the leucine zipper conformation is completely inhibited and only the more disordered species is observed, providing a novel method to study the effect of interactions of disordered systems and subsequent inhibition of the formation of an ordered helical complex.
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Molecular dynamics studies of the STAT3 homodimer:DNA complex: relationships between STAT3 mutations and protein-DNA recognition.
J Chem Inf Model
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Signal Transducers and Activators of Transcription (STAT) proteins are a group of latent cytoplasmic transcription factors involved in cytokine signaling. STAT3 is a member of the STAT family and is expressed at elevated levels in a large number of diverse human cancers and is now a validated target for anticancer drug discovery.. Understanding the dynamics of the STAT3 dimer interface, accounting for both protein-DNA and protein-protein interactions, with respect to the dynamics of the latent unphosphorylated STAT3 monomer, is important for designing potential small-molecule inhibitors of the activated dimer. Molecular dynamics (MD) simulations have been used to study the activated STAT3 homodimer:DNA complex and the latent unphosphorylated STAT3 monomer in an explicit water environment. Analysis of the data obtained from MD simulations over a 50 ns time frame has suggested how the transcription factor interacts with DNA, the nature of the conformational changes, and ways in which function may be affected. Examination of the dimer interface, focusing on the protein-DNA interactions, including involvement of water molecules, has revealed the key residues contributing to the recognition events involved in STAT3 protein-DNA interactions. This has shown that the majority of mutations in the DNA-binding domain are found at the protein-DNA interface. These mutations have been mapped in detail and related to specific protein-DNA contacts. Their structural stability is described, together with an analysis of the model as a starting-point for the discovery of novel small-molecule STAT3 inhibitors.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.