Scientists move closer to 'holy grail' of catalyst design

Washington, August 19 : Scientists at the University of Southern California have devised a way to design new catalysts, molecules that speed up chemical reactions without participating in them, which can help advance thousands of industrial and biological processes.

"The Holy Grail of enzyme catalysis and the ultimate manifestation of understanding of this process is the ability to design enzymes," said senior author Arieh Warshel, professor of chemistry at USC College.

Describing his research in the online edition of the journal PNAS, he listed drug production, environmental chemistry and bioremediation as areas that could be revolutionized by custom-designed enzymes.

Warshel also described a computational model that explains a key aspect of catalyst function, and suggests a design strategy.

Scientists have long championed the "lock and key" model, which holds that a catalyst works by exquisitely surrounding and matching the reacting system (the substrate).

Warshel's research team has now published papers in support of an alternate theory based on electrical attraction, which say that a perfect physical fit between catalyst and substrate is not necessary.

"What really fits is the electrostatic interaction between the enzyme active site to the substrate charges at the so-called transition state, where the bonds are halfway to being broken," Warshel said.

If he is correct, catalyst and substrate would be less like lock and key, and more like two magnets.

His model reproduced new experimental data showing that a natural enzyme and its engineered, structurally different counterpart both have the same catalytic power, despite being very different from each other.

Warshel says that the engineered enzyme can take the shape of many keys, with all fitting electrostatically in the same lock, something that should offer a new option for enzyme design.

ANI