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Expression Analysis of Mammalian Linker-histone Subtypes
Published on: March 19, 2012
Human p8 is a HMG-I/Y-like protein with DNA binding activity enhanced by phosphorylation
J A Encinar1, G V Mallo, C Mizyrycki
1Centro de Biologia Molecular y Celular, Universidad Miguel Hernández, 03202, Elche, Alicante, Spain.
The Journal of Biological Chemistry
|November 1, 2000
Summary
Human p8 (hp8) protein, affected in pancreatitis, functions similarly to High Mobility Group proteins. Phosphorylation by protein kinase A (PKA) enhances its DNA binding and structural stability.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Human p8 (hp8) is a nucleoprotein implicated in acute pancreatitis.
- Its biochemical and DNA-binding properties are not fully understood.
- Comparison with High Mobility Group (HMG) proteins is suggested by preliminary data.
Purpose of the Study:
- To elucidate the biochemical characteristics of hp8.
- To determine its solution conformation and DNA binding capabilities.
- To investigate the effect of phosphorylation on hp8 structure and function.
Main Methods:
- Circular dichroism (CD) spectroscopy (near- and far-UV).
- Fourier transform infrared (FTIR) spectroscopy.
- Nuclear Magnetic Resonance (NMR) spectroscopy.
- Electrophoretic gel shift assays.
- Protein kinase A (PKA) phosphorylation assays.
Main Results:
- hp8 exhibits properties similar to HMG-I/Y proteins.
- hp8 is monomeric and partially unfolded in solution.
- Non-phosphorylated hp8 binds DNA weakly.
- Phosphorylation by PKA increases hp8's secondary structure content.
- Phosphorylated hp8 (PKAhp8) exhibits significantly enhanced DNA binding.
Conclusions:
- Despite limited sequence homology, hp8 is functionally a HMG-I/Y-like protein.
- Phosphorylation by PKA is a key regulatory mechanism for hp8's DNA-binding activity.
- hp8's altered DNA binding upon phosphorylation may be relevant to its role in pancreatitis.
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These groups modify specific amino acids in a protein.
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