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PIP-on-a-chip: A Label-free Study of Protein-phosphoinositide Interactions
Published on: July 27, 2017
Pb2+ as modulator of protein-membrane interactions
Krystal A Morales1, Mauricio Lasagna, Alexey V Gribenko
1Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA.
Journal of the American Chemical Society
|May 28, 2011
Summary
Lead (Pb2+) binds to the C2α domain of Protein Kinase Cα (PKCα) with higher affinity than calcium (Ca2+), impacting its membrane binding and potentially contributing to lead toxicity.
Area of Science:
- Biochemistry
- Toxicology
- Structural Biology
Background:
- Lead (Pb2+) is an environmental toxin that mimics essential divalent metal ions.
- The molecular mechanisms underlying lead toxicity are not fully understood.
- Protein Kinase Cα (PKCα) is a known molecular target of lead.
Purpose of the Study:
- To investigate the structural and membrane-binding effects of Pb2+ on the C2α domain of PKCα.
- To elucidate the molecular interactions between Pb2+ and C2α.
Main Methods:
- Nuclear Magnetic Resonance (NMR) spectroscopy
- Isothermal Titration Calorimetry (ITC)
- X-ray crystallography
- Förster Resonance Energy Transfer (FRET) spectroscopy
Main Results:
- C2α binds Pb2+ with higher affinity than Ca2+.
- Crystal structures revealed Pb2+ coordination requires side-chain rotation, with coexisting holodirected and hemidirected geometries.
- Pb2+ displaces Ca2+ from C2α and competes for membrane-binding sites on lipid bilayers.
Conclusions:
- Pb2+ interaction with C2α differs significantly from Ca2+.
- Pb2+ binding to C2α and its competition for membrane sites likely contribute to PKCα inhibition and lead toxicity.
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