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A hydrophobic cluster at the surface of the human plasma phospholipid transfer protein is critical for activity on high density lipoproteins.
A hydrophobic cluster at the surface of the human plasma phospholipid transfer protein is critical for activity on high density lipoproteins.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2001 Feb 23; Vol. 276 (8), pp. 5908-15. Date of Electronic Publication: 2000 Nov 16. - Publication Year :
- 2001
-
Abstract
- The plasma phospholipid transfer protein (PLTP) belongs to the lipid transfer/lipopolysaccharide binding protein (LT/LBP) family, together with the cholesteryl ester transfer protein, the lipopolysaccharide binding protein (LBP) and the bactericidal permeability increasing protein (BPI). In the present study, we used the crystallographic data available for BPI to build a three-dimensional model for PLTP. Multiple sequence alignment suggested that, in PLTP, a cluster of hydrophobic residues substitutes for a cluster of positively charged residues found on the surface of LBP and BPI, which is critical for interaction with lipopolysaccharides. According to the PLTP model, these hydrophobic residues are situated on an exposed hydrophobic patch at the N-terminal tip of the molecule. To assess the role of this hydrophobic cluster for the functional activity of PLTP, single point alanine mutants were engineered. Phospholipid transfer from liposomes to high density lipoprotein (HDL) by the W91A, F92A, and F93A PLTP mutants was drastically reduced, whereas their transfer activity toward very low density lipoprotein and low density lipoprotein did not change. The HDL size conversion activity of the mutants was reduced to the same extent as the PLTP transfer activity toward HDL. Based on these results, we propose that a functional solvent-exposed hydrophobic cluster in the PLTP molecule specifically contributes to the PLTP transfer activity on HDL substrates.
- Subjects :
- Amino Acid Sequence
Binding Sites
Carrier Proteins genetics
Humans
Membrane Proteins genetics
Models, Molecular
Molecular Sequence Data
Mutation
Protein Engineering
Recombinant Proteins metabolism
Sequence Alignment
Static Electricity
Acute-Phase Proteins
Carrier Proteins blood
Lipoproteins, HDL metabolism
Membrane Glycoproteins
Membrane Proteins blood
Phospholipid Transfer Proteins
Phospholipids metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 276
- Issue :
- 8
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 11083872
- Full Text :
- https://doi.org/10.1074/jbc.M008420200