**Crystal Structure of the Unprocessed Precursor of Kluyvera citrophila Penicillin G Acylase Reveals Mechanistic Insights into Autocatalytic Activation**
The structural maturation of penicillin G acylase (PGA) from Kluyvera citrophila (KcPGA) is a tightly regulated autocatalytic process essential for enzyme activation. This transformation involves the intramolecular cleavage of a…