Conformational changes of 2-human glycoprotein I and lipid order in lipid-protein complexes.

PAOLOROSSI, MARIANA; G. G. MONTICH

ELSEVIER SCIENCE BV

Año: 2011 vol. 1808 p. 2167 - 2167

e studied the conformation of β2- human glycoprotein (β2GPI) in solution and bound to the anionic lipids palmitoyl oleoyl phosphatidylglycerol (POPG), dimiristoyl phosphatidylglycerol (DMPG) and dipalmitoyl phosphatidylglycerol (DPPG) as a function of the temperature. We used the infrared amide I’ band to study the protein conformation, and the position of the antisymmetric stretching band of the methylene groups in the lipid hydrocarbon chains to study the lipid order. Lipid-protein complexes were studied in media of low and high ionic strength. In solution, β2GPI displayed a conformational pre-transition in the range 47-50 oC, characterized by a shift in the band of β secondary structure, previous to the main unfolding at 64 ºC. When the protein was bound to the anionic lipid membranes at 25 oC, a similar shift as in the pre-transition in solution was observed, together with an increase in the band corresponding to -helix secondary structure. Lipid-protei