Three-dimensional model of the human PAF receptor
A Kajihara1, H Komooka, K Kamiya
1School of Pharmaceutical Sciences, Kitasato University, Tokyo, Japan.
Journal of Lipid Mediators and Cell Signalling
|May 1, 1994
Summary
Researchers modeled the human platelet-activating factor (PAF) receptor, revealing conserved residues and a potential binding site. This structural insight into the PAF receptor aids understanding of G protein-coupled receptor mechanisms.
Area of Science:
- Biochemistry
- Structural Biology
- Molecular Pharmacology
Background:
- Platelet-activating factor (PAF) is a potent lipid mediator involved in inflammation and allergic responses.
- The human PAF receptor, a G protein-coupled receptor (GPCR), mediates PAF's diverse biological effects.
- Understanding the structural basis of PAF receptor function is crucial for developing targeted therapeutics.
Purpose of the Study:
- To construct a three-dimensional (3D) model of the human PAF receptor.
- To elucidate the structural features and potential ligand-binding mechanisms of the human PAF receptor.
- To investigate the conservation of key residues and their implications for receptor structure and function.
Main Methods:
- Amino acid sequence analysis of the human PAF receptor.
- Comparative modeling using the 3D structure of bacteriorhodopsin as a reference.
- Utilizing the BIOCES[E] computer-modeling system for model construction.
Main Results:
- Identified conserved residues important for structural and functional aspects of the PAF receptor.
- Developed a 3D model featuring seven alpha-helical transmembrane segments and an S-S bond.
- Revealed a negatively charged site within the transmembrane domain formed by Asp-63, Asn-285, and Asp-289, likely involved in PAF binding.
Conclusions:
- The 3D model suggests electrostatic attraction between the positively charged choline moiety of PAF and the negatively charged receptor site.
- The model provides insights into potential conformational changes induced by PAF binding, leading to G-protein activation.
- Structural conservation implies functional similarities with other G protein-coupled receptors.
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