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K Austin

Publications and source records attributed to K Austin.

22 records · Page 2Linked to original sources
PubMed1975

Comparison of membrane organization in mitochondria from yeast and rat liver by nuclear magnetic resonance spectroscopy.

Proton magnetic resonance (PMR) and carbon-13 magnetic resonance (CMR) spectra of intact, unsonicated yeast and rat liver motochondria show differences which may be correlated with the composition of the membranes. High resolution PMR and CMR signals in intact yeast mitochondria have been assigned to regions of fluid lipid-lipid interaction on the basis of spectra of extracted lipid and protein, and the temperature dependence of NMR signals from the intact membrane. PMR spectra suggest that about 20% of total yeast phospholipid is in regions where both intramolecular fatty acid chain mobility and lateral diffusion of entire phospholipid molecules are possible. No such regions apear to exist in rat liver mitochondria. For both yeast and rat liver mitochondria, comparison of PMR and CMR spectra suggests that about 50% of phospholipid appears to be in regions where intramolecular fatty acid chain motion is considerable, but lateral diffusion is restricted. The remaining phospholipid appears to have little inter- or intramolecular mobility. Since NMR observation of lipid extracts from membranes indicates that phospholipid-sterol interactions do not account for the spectra of intact mitochondria, these effects are interpreted in terms of extensive lipid-protein interactions.

Animals↗
PubMed1975

Proton magnetic resonance spectroscopy of promitochondrial membranes from yeast grown under different regimes of lipid supplementation.

Promitochondrial membranes, prepared from Saccharomyces cerevisiae grown anaerobically under different conditions of lipid supplementation, have been examined by PMR spectroscopy. Promitochondria from cells cultured anaerobically in media containing both unsaturated fatty acid and sterol supplements, or containing unsaturated fatty acid alone, yield high resolution spectra similar to those which are characteristic of aerobic mitochondria. By contrast, promitochondrial membranes from cells grown only with sterol supplementation in order to deplete unsaturated fatty acid and total phospholipid content of the organelles, yielded PMR spectra which were very substantially broadened. These spectra are similar to those obtained with rat liver mitochondria. PMR spectra of promitochondria from each cell type dispersed in trifluoroacetic acid, or of extracted lipids or residual proteins similarly dispersed, were different only in detail. It appears, therefore, that in the native state membranes of unsaturated fatty acid-depleted promitochondria are structurally different from promitochondria of the other two cell types. The difference may be a consequence of altered lipid-to-protein ratios, and thus of changes in the extent of lipid domain formation in the membranes of these organelles.

Anaerobiosis↗