Structure characterization of membrane bound and surface adsorbed protein.
X-ray standing waves (XSW) have been used to study the topology of the protein cytochrome c, bound to a negatively charged model membrane and adsorbed at a metal surface. At the metal surface, cytochrome c forms an hexagonally close-packed monolayer. A similar packing arrangement is observed at the surface of a self-assembled lipid film on silver. The data suggest that cytochrome c maintains its native globular structure upon surface binding and subsequent storage for an extended period. Further, the data are consistent with a protein docking mechanism wherein the heme plane is oriented perpendicular to and with its exposed edge facing the surface. This study demonstrates the utility of XSW as a new and powerful structural tool for investigating membrane- and surface-protein interactions.
Wang
J
J
Department of Chemistry, Ohio State University, Columbus 43210.
Wallace
C J
CJ
Clark-Lewis
I
I
Caffrey
M
M
D000327:Adsorption; D003574:Cytochrome c Group / Q000737:chemistry; D005453:Fluorescence; D008565:Membrane Proteins / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry*; D012645:Selenomethionine; D012834:Silver; D014965:X-Rays
D003574:Cytochrome c Group; D008565:Membrane Proteins; D011506:Proteins; D012834:Silver; D012645:Selenomethionine