Abstract
Liver X receptor (LXR) and peroxisome proliferator-activated receptor (PPAR) are two members of nuclear
receptors involved in the nutrient metabolisms of dietary fatty acid and cholesterol. They are found to be of
cross-talk function in that LXR regulates fatty acid synthesis and PPAR controls fatty acid degradation.
LXRs (LXR and LXR) function by forming obligate heterodimers with the retinoid X receptor (RXR),
and subsequently binding to specific DNA response elements within the regulatory regions of their target
genes. In this work, the kinetic features concerning LXR/RXR and LXR/PPAR interactions have been fully
investigated using surface plasmon resonance (SPR) technology. It is found that LXRs could bind to all the
three PPAR subtypes, PPAR, PPAR and PPAR with different binding affinities, and such receptor/
receptor interactions could be regulated by ligand binding. Moreover, molecular dynamics (MD) simulations
were performed on six typical complex models. The results revealed that ligands may increase the interaction
energies between the receptor interfaces of the simulated receptor/receptor complexes. The MD
results are in agreement with the SPR data. Further analyses on the MD results indicated that the ligand
binding might increase the hydrogen bonds between the interfaces of the receptor/receptor complex.