Multiphosphorylation-Dependent Recognition of Anti-pS2 Antibodies against RNA Polymerase II C-Terminal Domain Revealed by Chemical Synthesis.

Phosphorylation is a major constituent of the CTD code, which describes the set of post-translational modifications on 52 repeats of a YSPTSPS consensus heptad that orchestrates the binding of regulatory proteins to the C-terminal domain (CTD) of RNA polymerase II. Phospho-specific antibodies are used to detect CTD phosphorylation patterns. However, their recognition repertoire is underexplored due to limitations in the synthesis of long multiphosphorylated peptides.

Chemoenzymatic Synthesis of Glycopeptides to Explore the Role of Mucin 1 Glycosylation in Cell Adhesion.

Post-translational modifications affect protein biology under physiological and pathological conditions. Efficient methods for the preparation of peptides and proteins carrying defined, homogeneous modifications are fundamental tools for investigating these functions. In the case of mucin 1 (MUC1), an altered glycosylation pattern is observed in carcinogenesis.

Enhancing Auxiliary-Mediated Native Chemical Ligation at Challenging Junctions with Pyridine Scaffolds.

To expand the scope of native chemical ligation (NCL) beyond reactions at cysteine, ligation auxiliaries are appended to the peptide N-terminus. After the introduction of a pyridine-containing auxiliary, which provided access to challenging junctions (proline or β-branched amino acids), we herein probe the role of the pyridine-ring nitrogen. We observed side reactions leading to preliminary auxiliary loss.

Dissecting the role of protein phosphorylation: a chemical biology toolbox.

Protein phosphorylation is a crucial regulator of protein and cellular function, yet, despite identifying an enormous number of phosphorylation sites, the role of most is still unclear. Each phosphoform, the particular combination of phosphorylations, of a protein has distinct and diverse biological consequences. Aberrant phosphorylation is implicated in the development of many diseases.