US EPA

8315031 

Journal Article 

Structural comparisons of native and reaggregated membranes from Mycoplasma laidlawii and erythrocytes by X-ray diffraction and nuclear magnetic resonance techniques 

Metcalfe, JC; Metcalfe, SM; Engelman, DM 

1971 

1 

Biochimica et Biophysica Acta. Biomembranes
ISSN: 0005-2736
EISSN: 1879-2642 

241 

2 

412-421 

English 

10.1016/0005-2736(71)90041-1 

1. 1. Reaggregates of Mycoplasma membranes after dispersion in sodium dodecyl sulphate were indistinguishable structurally from native membranes by the criteria of composition, density, and electron microscopy. 2. 2. The X-ray diffraction patterns show that a lipid bilayer structure is reformed in the reaggregates, although the extent of the bilayer regions is probably less than in the native membranes. 3. 3. Probe experiments using nuclear magnetic relaxation measurements confirm that there are extensive interactions between the membrane components which exclude some of the binding sites for the probe molecules that are exposed in the separated lipid and protein components. Nevertheless, the reaggregated structures are readily distinguishable from the native membranes by this probe technique, which indicates that at least some of the membrane proteins must be incorrectly reassembled. 4. 4. The Mycoplasma membranes and their separated components are compared with similar preparations from erythrocyte membranes. The pattern of responses of both membrane systems to perturbation by benzyl alcohol as reported by the relaxation measurements is very similar. The data imply that the membranes have a common element of structural organisation. © 1971.