Effect of Asp122 Mutation on the Hydride Transfer in E. coli DHFR Demonstrates the Goldilocks of Enzyme Flexibility
| Autor: | Dan Thomas Major, Christopher M. Cheatum, Yaron Pshetitsky, Amnon Kohen, Anil R. Mhashal, Reuven Eitan |
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| Rok vydání: | 2018 |
| Předmět: |
Models
Molecular Stereochemistry Protein Conformation 010402 general chemistry medicine.disease_cause 01 natural sciences Catalysis Enzyme catalysis Protein structure Catalytic Domain 0103 physical sciences Dihydrofolate reductase Materials Chemistry medicine Escherichia coli Computer Simulation Physical and Theoretical Chemistry chemistry.chemical_classification Mutation Principal Component Analysis 010304 chemical physics biology Chemistry Escherichia coli Proteins Mutagenesis Active site Hydrogen Bonding 0104 chemical sciences Surfaces Coatings and Films Tetrahydrofolate Dehydrogenase Enzyme Models Chemical biology.protein Quantum Theory Thermodynamics Hydrogen |
| Zdroj: | The journal of physical chemistry. B. 122(33) |
| ISSN: | 1520-5207 |
| Popis: | Dihydrofolate reductase (DHFR) catalyzes the reduction of dihydrofolate (DHF) to tetrahydrofolate (THF) in the presence of NADPH. The key hydride transfer step in the reaction is facilitated by a combination of enzyme active site preorganization and correlated protein motions in the Michaelis-Menten (E:NADPH:DHF) complex. The present theoretical study employs mutagenesis to examine the relation between structural and functional properties of the enzyme. We mutate Asp122 in Escherichia coli DHFR, which is a conserved amino acid in the DHFR family. The consequent effect of the mutation on enzyme catalysis is examined from an energetic, structural and short-time dynamic perspective. Our investigations suggest that the structural and short-time dynamic perturbations caused by Asp122X mutations (X = Asn, Ser, Ala) are along the reaction coordinate and lower the rate of hydride transfer. Importantly, analysis of the correlated and principle component motions in the enzyme suggest that the mutation alters the coupled motions that are present in the wild-type enzyme. In the case of D122N and D122S, the mutations inhibit coupled motion, whereas in the case of D122A, the mutation enhances coupled motion, although all mutations result in similar rate reduction. These results emphasize a Goldilocks principle of enzyme flexibility, that is, enzymes should neither be too rigid nor too flexible. |
| Databáze: | OpenAIRE |
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