| | 1 | Author
| Nikolai Tuparev, Anelia Dobrikova, Stefka Taneva, Tzvetana Lazarova | Requires cookie* | | | Title
| Bacteriorhodopsin Thermal Stability: Influence of Bound Cations and Lipids on the Intrinsic Protein Fluorescence  | | | | Abstract
| Temperature -induced changes in protein intrinsic fluorescence of native, delipidated and deionized purple membranes are investigated. It is found that the removal of cations most strongly affects the protein and its thermal stability. The denaturation of dei-BR completes at 70 °C, while delipidated and native BR still maintain their native structure at this temper ature. Both, the quantum yield and the fluorescence maximum suggest correlation between the Trp-retinal coupling and protein structural stability. The low red shift of the fluorescence maximum caused by increasing of temperature indicates limited unfolding of bacteriorhodop sin upon denaturation. | | | |
Reference
| Z. Naturforsch. 55c, 355—360 (2000); received December 27 1999/February 23 2000 | | | |
Published
| 2000 | | | |
Keywords
| Bacteriorhodopsin, Deionization, Delipidation | | | |
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| default:Reihe_C/55/ZNC-2000-55c-0355.pdf | | | | Identifier
| ZNC-2000-55c-0355 | | | | Volume
| 55 | |
| 2 | Author
| Gertrude Swoboda, Wilhelm Hasselbach | Requires cookie* | | | Title
| Bile Salt Delipidation, Residual Phospholipids and Reactivation o f the Ca2+-ATPase from Sarcoplasmic Reticulum | | | | Abstract
| 1. Delipidation o f the Ca2+-ATPase o f sarcoplasmic reticulum membranes by gel chro matography employing ionic detergents (cholate, deoxycholate and mixtures o f both) in the presence of glycerol has been studied with respect to residual phospholipids and ATPase activi ties. 2. The extent o f delipidation depends on the detergent chosen and on the ionic strength o f the elution buffer. Increasing ionic strength favours a more effective removal o f phospholipids, down to about 1 phospholipid molecule per ATPase molecule. 3. The residual ATPase activities o f the delipidated preparations are negligibly low. Extensive restoration of the Ca2+-dependent ATPase activity has been achieved by oleic acid, a lysolecithin (myristoylglycerophosphocholine) and a lecithin (dimyristoylglycerophosphocholine). The per centage of reactivation by oleate depends linearly on the amount o f residual phospholipids and on the detergent employed. 4. After gel filtration through an Ultrogel or Sepharose column containing 1% cholate in the elution buffer the delipidated ATPase is eluted as a reactivatable high molecular aggregate, whereas 1% deoxycholate favours the formation o f completely lipid-free monomeric units which cannot be reactivated, however. A high molecular aggregate is also formed in deoxycholate, the ratio of monomer to polymer depending on the solubilizing and elution conditions. 5. The residual lipids are always composed o f a mixture o f all different lipid classes present in the native sarcoplasmic vesicles, even at high degrees o f delipidation. Specific changes with vary ing extent of delipidation were not detected. | | | |
Reference
| Z. Naturforsch. 37c, 289—298 (1982); received December 7 1981 | | | |
Published
| 1982 | | | |
Keywords
| Sarcoplasmic Reticulum, Bile Salts, Delipidation, Reactivation, Lipids | | | |
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| default:Reihe_C/37/ZNC-1982-37c-0289.pdf | | | | Identifier
| ZNC-1982-37c-0289 | | | | Volume
| 37 | |
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