The Table of Interface Forming Residues as the Specificity Indicator for Serine Proteases Bound to Different Inhibitors

We propose a novel method for defining the exclusive and exhaustive table of serine proteases specificity determining interface forming residues (IFR). The IFR are obtained by “hard body docking” among 73 structurally aligned, sequence wise non redundant, serine protease structures, with 3 inhibitors: ecotine, ovomucoid third domain inhibitor and basic pancreatic trypsin inhibitor. In silico constructed complexes offered a condition for determining which residues are participating, from both enzyme and inhibitor side, in the ensemble of amino acids that upon binding loose contact with a solvent. Our focus is on offering a thorough study on how the specificity is achieved among serine proteases even though they have very little difference in their tertiary structure (specifically if the position of catalytic triad residues is considered). Presented table of serine protease specificity based on IFR position occupation show clear variations among sub families such as: trypsines, chymotrypsines, elastases and thrombines.