Trypsin oxyanion hole, structure

The arrangement of S965, H746, and the oxyanion hole suggests that the classical steps of peptide-bond hydrolysis follow the sequence of the trypsin-like serine proteases, namely the formation of the tetrahedral adduct, the acyl-enzyme complex, and hydrolysis. Tricorn has been shown to exhibit both tryptic and chymotryp-tic specificities (Tamura et al. 1996a). The X-ray structure reveals that specificity for basic PI residues is conferred by D936 which is provided by the diad-related subunit (see Figures 10.9 and 10.10). 

Figure 4.2 Structure of the oxyanion hole of the active site of trypsin, complexed with a peptide inhibitor (PDB IPPE). The hydrogen atoms (in white) are only included when relevant for the hydrogen bonding geometry of the oxyanion hole. The dotted lines highlight the key interactions in the oxyanion hole.

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