Heme-Edge Residues Modulate Signal Transduction within a Bifunctional Homo-Dimeric Sensor Protein

Bifunctional enzymes, which contain two domains with opposing enzymatic activities, are widely distributed in bacteria, but the regulatory mechanism(s) that prevent futile cycling are still poorly understood. The recently described bifunctional enzyme, DcpG, exhibits unusual heme properties and is surprisingly able to differentially regulate its two cyclic dimeric guanosine monophosphate (c-di-GMP) metabolic domains in response to heme gaseous ligands. Mutagenesis of heme-edge residues was used to probe the heme pocket and resulted in decreased O2 dissociation kinetics, identifying roles for these residues in modulating DcpG gas sensing. In addition, the resonance Raman spectra of the DcpG wild type and heme-edge mutants revealed that the mutations alter the heme electrostatic environment, vinyl group conformations, and spin state population. Using small-angle X-ray scattering and negative stain electron microscopy, the heme-edge mutations were demonstrated to cause changes to the protein conformation, which resulted in altered signaling transduction and enzyme kinetics. These findings provide insights into molecular interactions that regulate DcpG gas sensing as well as mechanisms that have evolved to control multidomain bacterial signaling proteins.

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Work Title Heme-Edge Residues Modulate Signal Transduction within a Bifunctional Homo-Dimeric Sensor Protein
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Open Access
Creators
  1. Dayna C. Patterson
  2. Yilin Liu
  3. Sayan Das
  4. Neela H. Yennawar
  5. Jean Paul Armache
  6. James R. Kincaid
  7. Emily E. Weinert
License In Copyright (Rights Reserved)
Work Type Article
Publisher
  1. Biochemistry
Publication Date November 29, 2021
Publisher Identifier (DOI)
  1. https://doi.org/10.1021/acs.biochem.1c00581
Deposited July 26, 2022

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Version 1
published

  • Created
  • Added Patterson_v3.pdf
  • Added Creator Dayna C. Patterson
  • Added Creator Yilin Liu
  • Added Creator Sayan Das
  • Added Creator Neela H. Yennawar
  • Added Creator Jean Paul Armache
  • Added Creator James R. Kincaid
  • Added Creator Emily E. Weinert
  • Published
  • Deleted Patterson_v3.pdf
  • Added Patterson_Biochemistry_2021.pdf
  • Updated Publication Date Show Changes
    Publication Date
    • 2021-12-14
    • 2021-11-29