Enzyme function affected by changes in external surface

Enzyme function affected by changes in external surface
© iStock/nicolas_

Research shows changes to enzyme surfaces affects the enzyme function, this being the substrate specificity by modifying how densely it is packed inside.

These findings have the potential of leading the way for manipulating the enzyme function. The researchers from Ruhr-Universität Bochum (RUB), Germany, published their report in the journal Communications Biology.

Aspects of the research

The enzyme function of plants was analysed, and with the nitrilases, being very similar, the researchers were able to replace their components piece by piece.

Associate Professor Dr. Markus Piotrowski from the Department of Molecular Genetics and Physiology of Plants at RUB explained: “We have thus found that merely by swapping one single component on the surface, we could make one enzyme convert the substrate of another enzyme.”

Successful progress with electron microscopy

Electron microscopy was used by the researchers to investigate why a modification of the surface can affect the substrate binding inside and thus the enzyme function.

They found that the analysed nitrilases form greater helices that are big enough to be rendered visible under an electron microscope.

“We could thus see that changes to the surface resulted in enzyme molecules in the helix to be more or less densely packed,” describes Piotrowski.

“This, in turn, presumably causes the substrate binding site to be compressed more or less tightly.”

Therefore, in its more tightly compressed state, the binding pocket is no longer accessible to larger substrate molecules.

What can scientists do with this new research regarding enzyme function?

For researchers, nitrilases not only establishes a model of the evolution of enzymes but are also deployed in the chemical and pharmaceutical industry as biocatalysts.

Currently, experiments that have targeted the modification of these enzymes by altering their substrate binding site have mostly remained unsuccessful.

“Our results have shown that the quaternary structure, namely the number and arrangement of individual enzyme molecules, has to be taken into consideration.” Concludes Piotrowski.

Accordingly, targeted modifications of the enzyme function may be accomplished without performing any changes to the enzyme itself, but by simply compressing it into nitrilase helices with different densities.

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