Phosphorylatable buried residues at or close to functional sites. The figure shows examples of phosphorylatable buried residues that are found at or in the vicinity of binding sites for small or large molecules. All the structures are shown differentially colored from their amino- (cold colors) to their carboxyl-termini (hot colors), with the phosphosites in white space-filled representation and their bound substrate in dark gray unless stated otherwise. (a) Structure of human 5'-deoxy-5'-methylthioadenosine phosphorylase  (Protein Data Bank [PDB]: 1cb0) with an adenine molecule. (b) Structure of homodimeric human malate dehydrogenase type 2 bound to NAD co-factor (unpublished data; PDB: 2dfd). (c) Structure of the carboxyl-terminal C2 domain of human tricalbin modeled onto the C2 domain of phospatidylinositide 3-kinase C2 α  (PDB: 2b3r). (d) Structure of a histone dimer (red and light yellow) bound to DNA (green and cyan)  (PDB: 1kx5). (e) Structure of the homodimer formed by the zinc-finger domains of the estrogen receptor in complex with DNA (cyan and blue)  (PDB: 1hcq). A list with additional details of the examples, including links to the appropriate mtcPTM entries, can be found in Additional data file 2.