CHANGES IN LIPID DISTRIBUTION AND DYNAMICS IN DEGRANULATED RAT-LIVER ROUGH ENDOPLASMIC-RETICULUM DUE TO THE MEMBRANE ATTACHMENT OF POLYRIBOSOMES

被引:13
作者
KAIHOVAARA, P
RAULO, E
KINNUNEN, PKJ
机构
[1] UNIV HELSINKI, DEPT MED CHEM, SILTAVUORENPENGER 10, SF-00170 HELSINKI 17, FINLAND
[2] UNIV HELSINKI, DEPT BIOCHEM, LIPID RES LAB, SF-00170 HELSINKI 17, FINLAND
关键词
D O I
10.1021/bi00098a015
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Binding of rat liver polyribosomes to homologous degranulated rough endoplasmic reticulum (dRER) labeled with 10-(pyren-1-yl)decanoic acid (PDA) was studied. As a consequence of the membrane association of polysomes, the excimer/monomer fluorescence intensity ratios (I(e)/I(m)) decreased, thus indicating alterations in the dynamics and organization of lipids. These fluorescence changes were complete within approximately 1 min, in accordance with the tight binding of ribosomes to RER. In order to characterize the changes in membrane lipid dynamics in more detail, polysomes were covalently labeled with trinitrobenzenesulfonic acid so as to allow their use as Forster-type resonance energy-transfer acceptors while utilizing PDA as a donor. Accordingly, assuming the binding of native and quencher-labeled ribosomes to the PDA-labeled membranes to be identical, we were able to discriminate fluorescence changes (a) in the proximity of the ribosome binding site from (b) those arising in the surrounding ribosome-free membrane and beyond the effective quenching radii of the TNP residues coupled to polysomes. Our data suggest that lipids in the polysome attachment site of dRER are less mobile than those in the remaining, ribosome-free membrane. In addition, there appears to be a relative enrichment of the PDA probe in the polyribosome membrane attachment sites.
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页码:8380 / 8386
页数:7
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