BCHM 310 Lecture Notes - Lecture 32: Tev Protease, Cysteine Protease, Oxyanion
22 Dec 2018
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Document Summary
Oxyanion hole: hole/pocket where oxyanion can form the 2 h-bonds. Pocket in which backbone nh can donate h bonds to the oxyanion of ts and tetrahedral intermediate (not to s in es complex) Enzyme using binding e to position s aligns reacting groups optimally. Enzyme provides interactions specific to ts provides electrostatic stabilization of charge formed in ts. Chymotrypsin: cuts after fyw, has a large hydrophobic specificity pocket. Trypsin: cuts after kr, has a large + deep pocket where sides are hydrophobic but there is an asp- at the btm of the pocket interacts electrostatically w k/r. Elastase: cuts after small residues like ser, thr, val: couple aa sub (val + thr sub 2 gly of chymotrypsin) to pinch of the pocket so longer side chains cant fit in. Small changes in seq + structure can affect substrate specificity. Fewer optimal interactions decr binding affinity of the substrate: less optimal positioning of ts.
