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Josh's Project Page - RISE Summer 2006 |
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Intern: Joshua Fields, Materials Science and Engineering,
Cornell University
Mentor: Richard Chapleau
Faculty Supervisor: Martin Sagermann
Department: Chemistry and Biochemistry |
ENGINEERING PH CONTROLLED ALLOSTERY IN GLUTATHIONE-S-TRANSFERASE
The goal of the presented research is to introduce responsive allosteric
function into a protein to enable its remote control. We describe here two
specific mutants of the enzyme GST (glutathione-S-transferase) that were
engineered specifically to introduce allosteric response. We control the
allostery via the introduction of specific pH-sensitive residues. The charges
of the mutated residues (aspartate and histidine) can be reversibly toggled on
& off selectively by varying the proton concentration of the surrounding medium.
In the off state the mutant residue is neutral and has no effect on the
protein’s binding site. In the on state, however, the mutated residue becomes
charged and induces conformational changes that interfere with the binding
activity. We hypothesize that a structural change is transmitted through the
body of the protein molecule thus altering its binding site. Consequently, the
function of the newly created mutant proteins can be remotely controlled via
external pH adjustments.
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