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Capture Compound Mass Spectrometry - A Powerful Tool to Identify Novel c-di-GMP Effector Proteins
Published on: March 29, 2015
Progressive cyclic nucleotide-induced conformational changes in the cGMP-dependent protein kinase studied by small
J Zhao1, J Trewhella, J Corbin
1Chemical Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
The Journal of Biological Chemistry
|February 12, 1998
Summary
Bovine lung protein kinase G (PKG) undergoes significant structural changes upon cGMP binding, increasing its asymmetry. This conformational shift, driven by domain movement, is crucial for full enzyme activation.
Area of Science:
- Biochemistry
- Structural Biology
- Enzymology
Background:
- Protein kinase G (PKG) is a crucial enzyme in cellular signaling pathways.
- Understanding PKG's structure and conformational changes upon ligand binding is key to elucidating its activation mechanism.
Purpose of the Study:
- To quantitatively measure the overall structure of bovine lung PKG.
- To assess the structural events accompanying cGMP-induced activation of PKG.
Main Methods:
- Small-angle scattering (SAS) was used to determine the protein's structure in the absence and presence of cGMP.
- Fourier transform infrared spectroscopy (FTIR) was employed to investigate secondary structural changes.
Main Results:
- In the absence of cGMP, PKG exhibits a highly asymmetric structure (Rg = 45 Å, dmax = 165 Å).
- cGMP binding induces a 25-30% increase in Rg and dmax, indicating greater asymmetry and domain movement.
- Conformational changes are primarily due to topographical domain shifts, not altered secondary structures.
Conclusions:
- cGMP binding progressively increases PKG asymmetry, with full domain movement requiring binding to both high and low-affinity sites.
- These structural changes correlate with the full activation of the enzyme.
- This study provides the first quantitative structural insights into PKG activation by a small molecule ligand.
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