Catalytic promiscuity in Pseudomonas aeruginosa arylsulfatase as an example of chemistry-driven protein evolution.

In recent years, it has become increasingly clear that many enzymes are catalytically "promiscuous". This can provide a springboard for protein evolution, allowing enzymes to acquire novel functionality without compromising their native activities. We present here a detailed study of Pseudomonas aeruginosa arylsulfatase (PAS), which catalyzes the hydrolysis of a number of chemically distinct substrates, with proficiencies comparable to that towards its native reaction. We demonstrate that the main driving force for the promiscuity is the ability to exploit the electrostatic preorganization of the active site for the native substrate, providing an example of chemistry-driven protein evolution.