In the following section we use the set of class A β-lactamase structures to illustrate further system-specific analysis that can be done using KIN. The conserved interaction network derived from crystallographic data is rendered in Figure and clearly shows that most of the highly conserved interactions are inter-molecular hydrogen bonds within α-helices or hydrophobic contacts in the core of the protein. When the contact maps are plotted by interaction type, hydrogen bonding interactions clearly predominate, while dense interactions around residue 50 characterize the hydrophobic core (Figure ). We performed a structural alignment of all 69 class A βlactamases (Figure ) to the TEM-1 structure and observed the α-helices and the core of each protein to be structurally preserved among the majority of these structures with RMSD score of 0.42 Å, and are an important common feature across the β-lactamase fold.