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Published on: May 26, 2011
Internally bridging water molecule in transmembrane alpha-helical kink
Masashi Miyano1, Hideo Ago, Hiromichi Saino
1Structural Biophysics Laboratory, RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan. miyano@spring8.or.jp
Current Opinion in Structural Biology
|August 27, 2010
Summary
Bound water molecules stabilize transmembrane helical kinks in alpha-helical integral membrane proteins, forming cavities for ligand binding and potentially regulating protein function.
Area of Science:
- Structural Biology
- Biochemistry
- Membrane Protein Research
Background:
- Hundreds of membrane protein atomic coordinates are available in the Protein Data Bank (PDB).
- High-resolution structures (>2.5 Å) reveal amphiphiles and bound water molecules as integral components.
- Alpha-helical integral membrane proteins are crucial for cellular functions.
Purpose of the Study:
- To investigate the role of water molecules in the structure and function of alpha-helical integral membrane proteins.
- To analyze high-resolution structures for specific water molecule interactions.
- To understand how water influences protein conformation and activity.
Main Methods:
- Analysis of high-resolution atomic coordinates from the Protein Data Bank (PDB).
- Scrutiny of structural features, particularly transmembrane helical segments.
- Identification and characterization of bound water molecules and their interactions.
Main Results:
- Water molecules were observed to 'wedge' and stabilize large kink angles (30-40 degrees) in transmembrane helices.
- These water-stabilized kinks form inter-helical cavities, essential for ligand binding or active sites.
- Specific water molecules are implicated in mediating conformational changes for functional regulation.
Conclusions:
- Water molecules are crucial structural elements in alpha-helical integral membrane proteins.
- They play a key role in forming functional cavities and influencing protein conformational dynamics.
- Understanding these water-mediated interactions is vital for elucidating membrane protein function.
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