Approach to systematic analysis of serine/threonine phosphoproteome using Beta elimination and subsequent side effects: intramolecular linkage and/or racemisation.
Complete analysis of the phosphorylation of serine and threonine residues directly from biological extracts is still at an early stage and will remain a challenging goal for many years. Analysis of phosphorylated proteins and identification of the phosphorylated sites in a crude biological extract is a major topic in proteomics, since phosphorylation plays a dominant role in post-translational protein modification. Beta elimination of the serine/threonine-bound phosphate by alkali action generates (methyl)dehydroalanine. The reactivity of this group susceptible of nucleophilic attacks might be used as a tool for phosphoproteome analysis. Most of the known serine/threonine kinases recognize motifs in protein targets that are rich in lysine(s) and/or arginine(s). The (methyl)dehydroalanine resulting from beta elimination of the serine/threonine-bound phosphate by alkali action is likely to react with the amino groups of these neighboring amino acids. Furthermore, the addition reaction of dehydroalanine-peptides with a nucleophilic group more likely generates diastereoisomers derivatives. The internal cyclic bonds and/or the stereoisomer peptide derivatives thus generated confer resistance to trypsin cleavage and/or constitute stop signals for exopeptidases such as carboxypeptidase. This might form the basis of a method to facilitate the systematic identification of phosphorylated peptides.
Tinette
Sylvette
S
Institut National de la Recherche Agronomique (INRA) et Centre National de Recherche Scientifique (CNRS), Centre de Sophia Antipolis, Université de Nice, 400 Route des Chappes BP 167, France.
Feyereisen
René
R
Robichon
Alain
A
D000595:Amino Acid Sequence; D019295:Computational Biology / Q000379:methods*; D016208:Databases, Factual; D015394:Molecular Structure; D010750:Phosphoproteins / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D010766:Phosphorylation; D010768:Phosphoserine / Q000737:chemistry / Q000378:metabolism; D010769:Phosphothreonine / Q000737:chemistry / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D012694:Serine / Q000737:chemistry / Q000378:metabolism*; D013237:Stereoisomerism
D010750:Phosphoproteins; D010769:Phosphothreonine; D010768:Phosphoserine; D012694:Serine