Light
of specific wavelengths can be used to boost an enzyme’s function by as
much as 30-fold, potentially establishing a path to less expensive
biofuels, detergents and a host of other products.

   

In a paper published in The Journal of Physical Chemistry Letters,
a team led by Pratul Agarwal of the Department of Energy’s Oak Ridge
National Laboratory described a process that aims to improve upon
nature—and it happens in the blink of an eye.

   

“When
light enters the eye and hits the pigment known as rhodopsin, it causes
a complex chemical reaction to occur, including a conformational
change,” Agarwal said. “This change is detected by the associated
protein and through a rather involved chain of reactions is converted
into an electrical signal for the brain.”

   

With
this as a model, Agarwal’s team theorized that it should be possible to
improve the catalytic efficiency of enzyme reactions by attaching
chemical elements on the surface of an enzyme and manipulating them with
the use of tuned light.

   

The
researchers introduced a light-activated molecular switch across two
regions of the enzyme Candida antarctica lipase B, or CALB—which breaks
down fat molecules—identified through modeling performed on DOE’s Jaguar
supercomputer.

   

“Using
this approach, our preliminary work with CALB suggested that such a
technique of introducing a compound that undergoes a light-inducible
conformational change onto the surface of the protein could be used to
manipulate enzyme reaction,” Agarwal said.

   

While
the researchers obtained final laboratory results at industry partner
AthenaES, computational modeling allowed Agarwal to test thousands of
combinations of enzyme sites, modification chemistry, different
wavelengths of light, different temperatures and photo-activated
switches. Simulations performed on Jaguar also allowed researchers to
better understand how the enzyme’s internal motions control the
catalytic activity.

   

“This
modeling was very important as it helped us identify regions of the
enzyme that were modified by interactions with chemicals,” said Agarwal,
a member of ORNL’s Computer Science and Mathematics Division.
“Ultimately, the modeling helped us understand how the mechanical energy
from the surface can eventually be transferred to the active site where
it is used to conduct the chemical reaction.”

   

Agarwal
noted that enzymes are present in every organism and are widely used in
industry as catalysts in the production of biofuels and countless other
everyday products. Researchers believe this finding could have immense
potential for improving enzyme efficiency, especially as it relates to
biofuels.

Engineering a Hyper-catalytic Enzyme by Photoactivated Conformation Modulation

Source: Oak Ridge National Laboratory