Structure-Function Relationship of Sterol Carrier Protein from the Yeast Yarrowia lipolytica (YLSCP2)

BURGARDT, NOELIA. I.; PEREZ DE BERTI, FEDERICO J.; FERREYRA, RAUL G.; CÓRSICO, BETINA; ERMÁCORA, MARIO R.; CEOLÍN, MARCELO R.

Rio de Janeiro

Congreso; VII IberoAmerican Congress of Biophysics; 2009

Latin American Federation of Biophysical Societies

Introduction. The sterol carrier proteins (SCP2) are small soluble intracellular proteins highly conserved in all biological kingdoms. SCP2 are involved in lipid solubilization and transfer to membranes. The SCP2 spectrum of ligands is broad, including fatty acids, acyl-CoAs, sterols and phospholipids. The ligand binding site has L-shaped and seems to accommodate ligands differentially. The conformational plasticity of the binding site seems to be related to the binding mechanism, which is still unclear. Our aim is the study of the relationship between structure and function of YLSCP2. Methods. The effect of binding of various ligands on the structure and stability of the protein was studied by circular dichroism (CD), fluorescence, small angle X-ray scattering (SAXS) and thermal unfolding followed by CD. The ligands used were palmitic acid, cisparinaric acid, palmitoyl-CoA, 1,8-anilinonaphtalene sulfonic acid (ANS), cholesterol and dehydroergosterol (DHE). Results. We found that cis-parinaric acid and ANS induces destabilization in YLSCP2 unfolding. The secondary structure of YSCP2 decreases with palmitic acid and cholesterol binding. YLSCP2 fluorescence decrease with palmitoyl-CoA binding and FRET is observed with ANS and cis-parinaric acid. Conclusions. We found a differential effects of ligands on YLSCP2 structure and stability. Theses results may be useful to find a mechanism for the binding of ligands to SCP2.