Cationic cell penetrating peptides with fatty acyl groups improve siRNA-delivery by chitosan for gene therapy

Oct 16, 2018 10:00:00 AM

After thirty years of promise and setbacks, a number of gene therapies for inherited immune disorders, like hemophilia, eye and neurodegenerative disorders, and lymphoid cancers have recently been approved in the United States and Europe or are anticipated to receive approval in the near future. One approach to gene therapy is to suppress the expression of specific proteins by gene silencing using siRNA. Viral delivery systems can have issues of immunogenicity and mutagenesis. This has stimulated the development of non-viral delivery systems. El-Sayed and collaborators based in Egypt and the USA have shown that chitosan complexed with fatty-acyl derivatives of a cationic cell-penetrating peptide, CGKRK, shows promise as a method for delivering intact short interfering RNA (siRNA) to breast cancer cells in vitro.

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Topics: Peptide synthesis, Gene therapy, Cell penetrating peptide, Tribute peptide synthesizer, siRNA delivery

Enabling identification of phosphorylated cysteine: Novel chemoselective synthetic and analytical methods

Dec 5, 2017 10:32:31 AM

Protein phosphorylation plays a key role in the regulation of signaling pathways and many other cellular processes. Studies of phosphorylation have focused on serine, threonine and tyrosine amino-acid side chains, while the phosphorylation of other amino acids, such as phospho-histidine (pHis), -arginine (pArg), -lysine (pLys) and -cysteine (pCys), is less well understood. Studies have been hindered by technical limitations, primarily acid lability. To address this problem, Jordi Bertran-Vicente and colleagues have developed a novel chemoselective and stereochemically defined phosphorylation strategy for Cys residues.  The method employs the nucleophilic reactivity of P(III)-reagents (phosphites) with electrophilic disulfides. The research team has also developed a mass spectrometry-based proteomic approach to identify and characterize pCys sites that naturally occur in peptides. 

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Topics: Peptide synthesis, Tribute, Tribute peptide synthesizer, Protein phosphorylation, pCys