Singlet oxygen-mediated one-pot chemoselective peptide–peptide ligation

We here describe a furan oxidation based site-specific chemical ligation approach using unprotected peptide segments. This approach involves two steps: after photooxidation of a furan-containing peptide, ligation is achieved by reaction of the unmasked keto-enal with C- or N-terminal alpha-nucleophilic moieties of the second peptide such as hydrazine or hydrazide to form a pyridazinium or pyrrolidinone linkage respectively

One-pot Synthesis of the Tetracyclic Framework of the Aromatic <i>Erythrina</i> Alkaloids from Simple Furans

Conversion of a simple furan into the intact erythrinane skeleton in one synthetic operation has been accomplished. The one-pot reaction sequence begins with singlet oxygen photooxygenation of the furan and proceeds via a 2-pyrrolidinone formation, cyclization of the pendant aldehyde moiety and an <i>N</i>-acyliminium ion formation and terminates with a Pictet-Spengler-type aromatic substitution. The method has been used to achieve a rapid and highly effective formal synthesis of erysotramidine

5-Hydroxy-pyrrolone based building blocks as maleimide alternatives for protein bioconjugation and single-site multi-functionalization

Recent dramatic expansion in potential uses of protein conjugates has fueled the development of a wide range of protein modification methods; however, the desirable single-site multi-functionalization of proteins has remained a particularly intransigent challenge. Herein, we present the application of 5-hydroxy-1,5-dihydro-2H-pyrrol-2-ones (5HP2Os) as advantageous alternatives to widely used maleimides for the chemo- and site-selective labeling of cysteine residues within proteins. A variety of 5HP2O building blocks have been synthesized using a one-pot photooxidation reaction starting from simple and readily accessible furans and using visible light and oxygen. These novel reagents display excellent cysteine selectivity and also yield thiol conjugates with superior stability. 5HP2O building blocks offer a unique opportunity to introduce multiple new functionalities into a protein at a single site and in a single step, thus, significantly enhancing the resultant conjugate's properties

Clinical Utility of Functional RNA Analysis for the Reclassification of Splicing Gene Variants in Hereditary Cancer

Background: Classification of splicing variants (SVs) in genes associated with hereditary cancer is often challenging. The aim of this study was to investigate the occurrence of SVs in hereditary cancer genes and the clinical utility of RNA analysis. Material and Methods: 1518 individuals were tested for cancer predisposition, using a Next Generation Sequencing ( NGS) panel of 36 genes. Splicing variant analysis was performed using RT-PCR and Sanger Sequencing. Results: In total, 34 different SVs were identified, 53% of which were classified as pathogenic or likely pathogenic. The remaining 16 variants were initially classified as Variant of Uncertain Significance (VUS). RNA analysis was performed for 3 novel variants. Conclusion: The RNA analysis assisted in the reclassification of 20% of splicing variants from VUS to pathogenic. RNA analysis is essential in the case of uncharacterized splicing variants, for proper classification and personalized management of these patients