Expanding the ubiquitin code through post‐translational modification

Expanding the ubiquitin code through post-translational modification.

Ubiquitylation is among the most prevalent post-translational modifications (PTMs) and regulates numerous cellular functions. Interestingly, ubiquitin (Ub) can be itself modified by other PTMs, including acetylation and phosphorylation. Acetylation of Ub on K6 and K48 represses the formation and elongation of Ub chains. Phosphorylation of Ub happens on multiple sites, S57 and S65 being the most...

Expanding the Ubiquitin Code

Posttranslational modification of MDM2.

The functions of the MDM2 protein, in particular its E3 ubiquitin ligase activity and its ability to interact with a number of cellular proteins intimately involved in growth regulation, are modulated by sumoylation and multisite phosphorylation. These posttranslational mechanisms not only regulate the intrinsic activity of MDM2 in response to cellular stresses, but also govern its subcellular ...

Expanding the genetic code to study metalloproteins and protein posttranslational modifications

Genetic code expansion is a useful method to study metalloproteins and protein posttranslational modifications. We constructed several tyrosine and pyrrolysine tRNA synthetase libraries based on tyrosine and pyrrolysine tRNA synthetase/tRNA pairs to screen unnatural amino acids (UAAs) with similar chemical structure to tyrosine or lysine. We had incorporated several unnatural amino acids into p...

Expanding the genetic code.

Although chemists can synthesize virtually any small organic molecule, our ability to rationally manipulate the structures of proteins is quite limited, despite their involvement in virtually every life process. For most proteins, modifications are largely restricted to substitutions among the common 20 amino acids. Herein we describe recent advances that make it possible to add new building bl...