Different Solvent and Conformational Entropy Contributions to the Allosteric Activation and Inhibition Mechanisms of Yeast Chorismate Mutase

Allosteric regulation is important in many biological processes, including cell signaling, gene regulation, and metabolism. Saccharomyces cerevisiae chorismate mutase (ScCM) is a key homodimeric enzyme in the shikimate pathway responsible for the generation of aromatic amino acids, where it is allosterically inhibited and activated by Tyr and Trp, respectively. Our previous studies indicated that binding of both allosteric effectors is negatively cooperative, that is binding at one allosteric binding site discourages binding at the other, due to the entropic penalty of binding the second allosteric effector. We utilized variable temperature isothermal titration calorimetry (ITC) and nuclear magnetic resonance (NMR) experiments to better understand the entropic contributions to allosteric effector binding, including changes to solvent entropy and protein conformational entropy. Upon binding either Tyr or Trp, ScCM experiences a quenching of motions on the picosecond-to-nanosecond time scale, which we could relate to a loss of protein conformational entropy. Further ITC and NMR studies were consistent with the Tyr-bound form of ScCM being associated with more water molecules compared to the Trp-bound form and Tyr binding being associated with a less positive solvent entropy change. These studies provide insight into the role of structural dynamics in ScCM function and highlight the importance of solvent entropy changes in allosteric regulation, a historically underappreciated concept.

This document is the accepted version of a publication in 'Biochemistry', copyright © American Chemical Society. To access the final published work see https://doi.org/10.1021/acs.biochem.0c00277

Files

Metadata

Work Title Different Solvent and Conformational Entropy Contributions to the Allosteric Activation and Inhibition Mechanisms of Yeast Chorismate Mutase
Access
Open Access
Creators
  1. Scott D. Gorman
  2. Dennis Sean Winston
  3. Debashish Sahu
  4. David Boehr
Keyword
  1. Entropy
  2. Ligands
  3. Crystal structure
  4. Alkyls
License All rights reserved
Work Type Article
Publisher
  1. Biochemistry
Publication Date June 15, 2020
Subject
  1. Biochemistry
Language
  1. English
Publisher Identifier (DOI)
  1. 10.1021/acs.biochem.0c00277
Related URLs
Deposited February 24, 2021 10:58

Analytics

Collections

This resource is currently not in any collection.

Work History

Version 1
published

  • Created
  • Added Creator David Boehr
  • Added Creator Scott D. Gorman
  • Added Creator Dennis Sean Winston
  • Added Creator Debashish Sahu
  • Added GormanBoehr2021.pdf
  • Updated License Show Changes
    License
    • https://rightsstatements.org/page/InC/1.0/
  • Published

Version 2
published

  • Created
  • Deleted GormanBoehr2021.pdf
  • Added GormanBoehr2020_manuscript_revised_2.pdf
  • Updated Creator Scott D. Gorman
  • Updated Creator David Boehr
  • Updated Creator Dennis Sean Winston
  • Updated Creator Debashish Sahu
  • Updated Keyword, Publisher, Publisher Identifier (DOI), and 2 more Show Changes
    Keyword
    • Entropy, Ligands, Crystal structure, Alkyls
    Publisher
    • American Chemical Society
    • Biochemistry
    Publisher Identifier (DOI)
    • 10.1021/acs.biochem.0c00277
    Description
    • Allosteric regulation is important in many biological
    • processes, including cell signaling, gene regulation, and metabolism. Saccharomyces cerevisiae chorismate mutase (ScCM) is a key
    • homodimeric enzyme in the shikimate pathway responsible for the
    • generation of aromatic amino acids, where it is allosterically
    • inhibited and activated by Tyr and Trp, respectively. Our previous
    • studies indicated that binding of both allosteric effectors is
    • negatively cooperative, that is binding at one allosteric binding site
    • discourages binding at the other, due to the entropic penalty of
    • binding the second allosteric effector. We utilized variable
    • temperature isothermal titration calorimetry (ITC) and nuclear magnetic resonance (NMR) experiments to better understand
    • the entropic contributions to allosteric effector binding, including changes to solvent entropy and protein conformational entropy.
    • Upon binding either Tyr or Trp, ScCM experiences a quenching of motions on the picosecond-to-nanosecond time scale, which we
    • could relate to a loss of protein conformational entropy. Further ITC and NMR studies were consistent with the Tyr-bound form of
    • ScCM being associated with more water molecules compared to the Trp-bound form and Tyr binding being associated with a less
    • positive solvent entropy change. These studies provide insight into the role of structural dynamics in ScCM function and highlight
    • the importance of solvent entropy changes in allosteric regulation, a historically underappreciated concept.
    • the importance of solvent entropy changes in allosteric regulation, a historically underappreciated concept.
    • This document is the accepted version of a publication in 'Biochemistry', copyright © American Chemical Society. To access the final published work see https://doi.org/10.1021/acs.biochem.0c00277
    Related URLs
    • https://pubs.acs.org/doi/10.1021/acs.biochem.0c00277
  • Published