(Modeling proteins) (Chymotrypsin Mechanism: Step 1, Step 2, Step 3, Step 4, Step 5, Step 6)

Transition state between Steps 1 and 5 of Chymotrypsin Mechanism

  (PDB file) (ARC file)

This is a nonsense reaction.  Given a starting model, a water molecule adds across the Trp252-Thr253 peptide bond to give an ionized Thr253 plus a tetrahedral intermediate.  The transition state shows one of the water hydrogen atoms on Thr253, the serine hydrogen on the water, and the serine oxygen starting to bond to Trp252 carbonyl carbon. Energetically, this reaction is not possible. Step_1_2_Transition_state. Toggle display all Toggle center picture Fit to screen Interesting parts: His57 Gly193 Asp194 Ser195 Trp252 Thr253 H2O Toggle spin Toggle stereo