Fig. 4: Pfam-peptide interactions.

a Three trypsin-peptide interface clusters. The number of peptides indicates the number of unique peptide sequences; the peptide sequences of each cluster can be found on each cluster page on ProtCID. The Pfam domains are colored in green and the peptides are colored in magenta. The first cluster mostly constists of human thrombin bound to peptides from hirudin from leeches. The peptides of the second cluster is a large set of substrates bound to the active sites of trypsin-like proteases. The peptides of the third cluster are cleavage products, created by internal cleavage by activating enzymes. b Pkinase–peptide interactions show the binding sites of substrates, activators, and inhibitors. Cluster 1 shows the peptides binding to active sites as inhibitors or substrates. Cluster 2 contains peptides binding to a groove between α_d and α_e and the β7–β8 reverse turn on the kinase C-terminal domain. Cluster 3 is a small cluster of peptides binding to the N-terminal groove.