Structure and function of Sterol Carrier Protein 2 (SCP2) from the oleaginous yeast Yarrowia lipolytica

FERREYRA, RAÚL G.; ERMÁCORA, MARIO R.; GIANOTTI, ALEJO R.

Erice

Workshop; 54th Course: Cryo 3D Electron Microscopy; 2019

International School of Crystallography

AbstractSterol Carrier Protein 2 (SCP2) is a nonspecific lipid transferprotein that has been implicated in lipid binding and transfer activities. SCP2 is present in all forms of life (Eukarya, Bacteria and Archaea) as a module of multidomain proteins or as stand-alone domain. Most SCP2 domains pertain to three major families and are frequently found as stand-alone or at the C-termini of lipid related peroxisomal enzymes, acetyltransferases causing bacterial resistance, and bacterial environmentally important sulfatases.We have shown that the SCP2 from the dimorphic yeast Yarrowia lipolytica, a model microorganism for studying hydrophobic substrates utilization, is a 14 kDa basic protein inducible by fatty acids. This protein is located in the yeast peroxisomes and is able to bind and transfer a variety of lipids to membranes by a collision-mediated mechanism. Our results on SCP2 X-ray diffraction showed the lipid binding site in the protein as a large system of interconnected tunnels and surface pockets partially occupied by palmitate.In this poster we present the structural features of this SCP2 domain: analyzed the structural basis of the fold, the classification of SCP2 domains and identified structure-determined sequence features. Also, we characterized the overall hydrophobicity, fluidity, and dipolar dynamics of the binding site of SCP2 using the environmentally-sensitive fluorescent probe Laurdan.