Structural analysis of membranes from photosynthetic bacteria by SANS
Istituto di Scienze Fisiche, Facoltà di Medicina, Università - Via Ranieri 65, 60131 Ancona and INFM, unit of Ancona, Italy
2 Dipartimento di Biologia, Università - Via Irnerio 42, 40126 Bologna, Italy
3 Laboratoire Leon Brillouin (Laboratoire commun CEA-CNRS) CEN Saclay, 91191 Gif-sur-Yvette, France and INFM, unit of Ancona, Italy
Accepted: 16 January 1997
We use contrast variation small-angle neutron scattering to characterize the topology of the photosynthetic membrane of Rhodobacter capsulatus. Native membranes appear significantly asymmetric, while membranes treated to remove the soluble part of the ATPase enzyme complex are symmetric. Data are consistent with models in which the hydrophilic portions of the whole membrane proteins protrude on both sides of the membrane and the soluble ATPase part projects from the outer surface. Results support the notion that energy coupling membranes are asymmetric and confirm that this is mainly due to the soluble ATPase part.
PACS: 87.15.By – Structure, bonding, conformation, configuration, and isomerism of bio mol e cules / 87.22.Bt – Membrane and subcellular physics and structure / 61.12.Ex – Neutron scattering techniques (including small-angle scattering)
© EDP Sciences, 1997