Post-Translational Modifications and Functional Sites

An important aspect in the sequence analysis of proteins is the detection of functional sites such as the active site, ligand binding site, signal sequence/cleavage site and post-translational modification sites. Generally, a prior knowledge concerning the chemical nature of these sites is available. For example, the active triad (Ser-His-Asp/Glu) of serine 

The Catalytic Site Atlas (CSA) at http //www.ebi.ac.uk/thomton-srv/databases/CSA provides catalytic residue annotation for enzymes in the PDB (Porter et al, 2004). The residues are defined as catalytic if they fulfill any one of the criteria namely  

alteration of the pKa of a residue or water molecule directly involved in the catalytic 

TABLE 16.9 Online resources for functional and post-translational modification sites 

CSA http //www.ebi.ac.uk/thomton-srv/databases/CSA Catalytic residues in enzymes 

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