Control of enzyme activity by an engineered disulfide bond |
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Authors: | M Matsumura B W Matthews |
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Affiliation: | Institute of Molecular Biology, University of Oregon, Eugene 97403. |
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Abstract: | A novel approach to the control of enzyme catalysis is presented in which a disulfide bond engineered into the active-site cleft of bacteriophage T4 lysozyme is capable of switching the activity on and off. Two cysteines (Thr21----Cys and Thr142----Cys) were introduced by oligonucleotide-directed mutagenesis into the active-site cleft. These cysteines spontaneously formed a disulfide bond under oxidative conditions in vitro, and the catalytic activity of the oxidized (cross-linked) T4 lysozyme was completely lost. On exposure to reducing agent, however, the disulfide bond was rapidly broken, and the reduced (non-cross-linked) lysozyme was restored to full activity. Thus an enzyme has been engineered such that redox potential can be used to control catalytic activity. |
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