Protein heat denaturation and study of membrane lipid-protein interactions by spin label ESR.
ABSTRACT Spinach chloroplast membranes labelled with stearic acid-spin probe-bearing nitroxyl (label) moiety at 5th, 9th, 12th, 13th, 14th or 16th carbon locations with respect to the carboxylic group of stearic acid were studied (in the dark) by electron spin resonance (ESR) spectroscopy. Spectra were recorded at sample temperatures of 5, 30 and 67 degrees C. After heat denaturation of the membrane proteins for 5 min at 67 degrees C, the spectra were re-recorded at 30 and 5 degrees C for comparison. The results unequivocally show that membrane lipid fatty-acyl chains become substantially more rigid after protein heat-denaturation. The data throw light on the degree of lipid-protein interactions at various microlocations along the length of fatty-acyl chains of the membrane lipid matrix.
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Article: Protein heat denaturation and study of membrane lipid-protein interactions by spin label ESR.
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ABSTRACT: Spinach chloroplast membranes were studied by natural abundance carbon-13 nuclear magnetic resonance (13C-NMR) spectroscopy in their normal state and after heat denaturation of membrane proteins. The membrane proteins were denatured by raising the temperature of the sample to 67 degrees C for 5 minutes [YashRoy, R.C. (1991) J. Biochem. Biophys. Methods 22, 55-59]. Line-broadening of 13C-NMR resonances arising from the 1st (carbonyl), 7th, 9th and 12th carbon atom of fatty-acyl chains with reference to the carbonyl (C-1) group shows increased immobilization of lipid fatty-acyl chains at these locations, obviously caused by changes in interactions between membrane lipids and proteins upon heat denaturation of membrane proteins.Journal of Biochemical and Biophysical Methods 10/1991; 23(3):259-61. DOI:10.1016/0165-022X(91)90019-S · 1.81 Impact Factor
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ABSTRACT: Spinach leaves were studied by high resolution 13C-NMR spectroscopy. The spectra obtained, though highly complex, showed some distinct resonances assignable to carbons of lipids of the chloroplast membranes, thereby offering a novel way for studying the chloroplast membranes in situ.Indian journal of biochemistry & biophysics 07/1992; 29(3):306-8. · 1.08 Impact Factor
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ABSTRACT: Employing negative-staining electron microscopy, convincing evidence has been obtained for the destabilisation of multilamellar organisation of aqueous dispersions of chloroplast thylakoid membrane lipids, to an inverted micellar structure under the influence of sucrose solution. The present study provides a new insight into the phase behaviour of a naturally existing galactolipid-rich lipid mixture consequent to interaction with a kosmotropic reagent.Biochimica et Biophysica Acta 05/1994; 1212(1):129-33. DOI:10.1016/0005-2760(94)90198-8 · 4.66 Impact Factor
Questions & Answers about this publication
- Can global warming denature proteins in biomembrane systems of earthlings and affect protein dynamics in cellular membranes vis a vis this ref? Environmental temperatures may soar above 50 deg C in tropics. What effect can it have on cells, body and life of animals and plants?Following