| | 2 | Author
| R. Udolf Schendel, W. Olfhart, R. Üdiger | Requires cookie* | | | Title
| Electrophoresis and Electrofocusing of Phytochrome from Etiolated Avena sativa L  | | | | Abstract
| Phytochrome from etiolated oat seedlings (Avena sativa L.) was investigated by "native" gel electrophoresis and by isoelectric focusing. At pH 8 . 8 the Pfr form migrated faster than the Pr form in electrophoresis. We assume a difference in the surface charge rather than a difference in shape for the phytochrome forms. This assumption was confirmed by isoelectric focusing which clearly showed relatively more negative charge in the Pfr form than in the Pr form. The role of the peptide region from residue 323 to 360 is discussed in this connection. It carries 9 negatively charged residues, it is exposed only in the Pfr form and it has already been described as a signal region for rapid protein degradation (PEST sequence, see Rogers et al., Science 234, 364—368, 1986). The experiments on electrofocusing revealed a microheterogeneity of phytochrome which was present in the native state as well as in the completely unfolded state. The most probable reason could be either posttranslational modification or genetic polymorphism of phytochrome in oat. | | | |
Reference
| Z. Naturforsch. 44c, 12 (1989); received November 25 1988 | | | |
Published
| 1989 | | | |
Keywords
| Microheterogeneity, Pest Sequence, Phytochrome Denaturation, Protein Conformation | | | |
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| | | | | TEI-XML for
| default:Reihe_C/44/ZNC-1989-44c-0012.pdf | | | | Identifier
| ZNC-1989-44c-0012 | | | | Volume
| 44 | |
| 3 | Author
| Gianfranco Menestrina, Flavia Pasquali | Requires cookie* | | | Title
| Effects of Carbohydrates on the Ion Conductance of the Hemocyanin Channel | | | | Abstract
| The effects o f glucose and sucrose on the ionic conductance properties o f the channel formed by Megathura crenulata hemocyanin in planar lipid bilayers have been studied using m em branes o f different compositions. It was found that glucose at high concentrations strongly affects the time constants o f the current relaxations observed in m em branes containing many channels after a step in the voltage clamp from ground to a positive value. At m uch lower concentrations both sucrose and glucose strengthened the binding o f Ba2+ to the protein, what in turn has the effect to shift the conductance voltage curve o f the pore towards negative potentials. The possible mechanism underlying these effects and the analogies with other studies on the interaction o f sugars and alcohols with proteins have been discussed. | | | |
Reference
| Z. Naturforsch. 40c, 85—9 (1985); received October 25 1984 | | | |
Published
| 1985 | | | |
Keywords
| Hemocyanin Channel, Planar Lipid Bilayer, Carbohydrates, D ivalen t Cations, Protein Conformations | | | |
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| default:Reihe_C/40/ZNC-1985-40c-0085.pdf | | | | Identifier
| ZNC-1985-40c-0085 | | | | Volume
| 40 | |
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