par Bryson, E A;Rankin, S E;Goormaghtigh, Erik 
;Ruysschaert, Jean Marie ;Watts, Anthony;Pinheiro, T J
Référence European journal of biochemistry / FEBS, 267, 5, page (1390-1396)
Publication Publié, 2000-03
;Ruysschaert, Jean Marie ;Watts, Anthony;Pinheiro, T JRéférence European journal of biochemistry / FEBS, 267, 5, page (1390-1396)
Publication Publié, 2000-03
Article révisé par les pairs
| Résumé : | Apocytochrome c (apocyt c), which in aqueous solution is largely unstructured, acquires an alpha-helical conformation upon association with lipid membranes. The extent of alpha-helix induced in apocyt c is lipid-dependent and this folding process is driven by both electrostatic and hydrophobic lipid-protein interactions. The structural and dynamic properties of apocyt c in lipid membranes were investigated by attenuated total reflection Fourier transform infrared spectroscopy combined with amide H-D exchange kinetics. Apocyt c acquires a higher content of alpha-helical structure with negatively charged membranes than with zwitterionic ones. For all membranes studied here, the helices of these partially folded states of apocyt c have a preferential orientation perpendicular to the plane of the lipid membrane. The H-D exchange revealed that a small fraction of amide protons of apocyt c, possibly associated with a stable folded domain protected by the lipid, remained protected from exchange over 20 min. However, a large fraction of amide protons exchanged in less than 20 min, indicating that the helical states of apocyt c in lipid membranes are very dynamic. |
