NTRS - NASA Technical Reports Server

Back to Results
Salt modulates the stability and lipid binding affinity of the adipocyte lipid-binding proteinsAdipocyte lipid-binding protein (ALBP or aP2) is an intracellular fatty acid-binding protein that is found in adipocytes and macrophages and binds a large variety of intracellular lipids with high affinity. Although intracellular lipids are frequently charged, biochemical studies of lipid-binding proteins and their interactions often focus most heavily on the hydrophobic aspects of these proteins and their interactions. In this study, we have characterized the effects of KCl on the stability and lipid binding properties of ALBP. We find that added salt dramatically stabilizes ALBP, increasing its Delta G of unfolding by 3-5 kcal/mol. At 37 degrees C salt can more than double the stability of the protein. At the same time, salt inhibits the binding of the fluorescent lipid 1-anilinonaphthalene-8-sulfonate (ANS) to the protein and induces direct displacement of the lipid from the protein. Thermodynamic linkage analysis of the salt inhibition of ANS binding shows a nearly 1:1 reciprocal linkage: i.e. one ion is released from ALBP when ANS binds, and vice versa. Kinetic experiments show that salt reduces the rate of association between ANS and ALBP while simultaneously increasing the dissociation rate of ANS from the protein. We depict and discuss the thermodynamic linkages among stability, lipid binding, and salt effects for ALBP, including the use of these linkages to calculate the affinity of ANS for the denatured state of ALBP and its dependence on salt concentration. We also discuss the potential molecular origins and potential intracellular consequences of the demonstrated salt linkages to stability and lipid binding in ALBP.
Document ID
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Schoeffler, Allyn J.
(Louisiana State University Baton Rouge, Louisiana 70803, United States)
Ruiz, Carmen R.
Joubert, Allison M.
Yang, Xuemei
LiCata, Vince J.
Date Acquired
August 21, 2013
Publication Date
August 29, 2003
Publication Information
Publication: The Journal of biological chemistry
Volume: 278
Issue: 35
ISSN: 0021-9258
Subject Category
Life Sciences (General)
Distribution Limits
NASA Discipline Cell Biology
Non-NASA Center

Available Downloads

There are no available downloads for this record.
No Preview Available