Joy Cote PhD ’18, Cody Hecht ’18, MA’19, and Erika Taylor, associate professor of chemistry, are the co-authors of a study that explores how opposite charges on our substrate and enzyme cause a protein to change shape when the substrate binds.
The study, titled “Opposites Attract: Escherichia coli Heptosyltransferase I Conformational Changes Induced by Interactions between the Substrate and Positively Charged Residues,” appears in the February 2020 issue of Biochemistry.
“If you can imagine how the opposite charges of magnets are attracted toward each other, then you understand the results of this paper,” Taylor explained. “The enzyme uses positively-charged amino acids to attract its substrate, which has many negatively charged regions. The attraction of the enzyme to the substrate even causes the shape of the protein to change, closing in on the substrate, like the way the fingers of your hand might bend to grasp a ball.”
The researchers describe how they introduced mutations into the amino acid sequence of this protein, and observated how these mutated residues impact the reactivity and protein behavior both in laboratory experiments and in computational studies.
“The amazing thing about these interactions is that they allow the protein to be stable at 203 degrees F, which is almost the boiling point of water, when normally proteins from Escherichia coli are only stable near human body temperatures,” Taylor said.
Although it isn’t clear exactly how the protein becomes so stable, the researchers are intrigued by how the interactions of these charged groups play a major role in that stabilization process.