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W Rüdiger

Publications and source records attributed to W Rüdiger.

At least 55 records · Page 3Linked to original sources
PubMed1986

The complete amino-acid sequence of C-phycoerythrin from the cyanobacterium Fremyella diplosiphon.

The amino-acid sequences of both subunits of C-phycoerythrin from the cyanobacterium Fremyella diplosiphon have been determined. The alpha-subunit contains 164 amino acid residues, two phycoerythrobilin (PEB) chromophores and has a molecular mass of 18,368 Da (protein: 17,192 Da + 2 PEB, one PEB accounting for 588 Da). The beta-subunit consists of 184 residues, three PEB chromophores and has a molecular mass of 20,931 Da (protein: 19,168 Da and 3 PEB: 1,764 Da). The five PEB chromophores (open chain tetrapyrroles) are covalently bound to six cysteine residues (one of them doubly bound to two cysteine residues). On the alpha-subunit, the first chromophore was found at position 84, homologous to the chromophore binding site of the other biliproteins APC, PC and PEC. The second chromophore, unique for the alpha-subunit of PE, is inserted together with a pentapeptide at position 143 a. On the beta-subunit, a doubly bound chromophore is attached to cysteine residues 50 and 61, similar to the rhodophytan phycoerythrins (B-PE and R-PE). The second and third chromophores were found at positions 84 and 155, homologous to the other biliproteins. A unique peptide insertion of 14 amino acid residues (without chromophore) was found at position 141 a-o in the beta-subunit and probably is located in the three-dimensional model near the additional chromophores of the C-PE alpha- and beta-subunits. Both additional chromophores of the C-PE alpha- and beta-subunit may be located at the periphery of the C-PE-trimer. The amino-acid sequence homology between C-PE alpha- and beta-subunit is 26% and to the alpha- and beta-subunits of C-PC from Mastigocladus laminosus 49% and 48%, respectively.

Amino Acid Sequence↗
PubMed1983

Chromophore structure of the physiologically active form (P(fr)) of phytochrome.

Chromopeptides were prepared by proteolytic digestion of phytochrome (far-red absorbing form, P(fr)) and of phycocyanin. The phycocyanobilin peptide, the chromophore of which is Z,Z,Z-configurated, was modified to the Z,Z,E isomeric chromophore. It has been demonstrated earlier that the P(fr) chromopeptide and the Z,Z,E-configurated phycocyanin chromopeptide behave similarly with regard to spectral and chromatographic properties and reactivity. We present evidence here, obtained by high-resolution (1)H NMR spectroscopy, that both the modified phycocyanobilin chromophore and the phytochrome chromophore obtained directly from P(fr) are 15E-configurated.

Journal Article↗
PubMed1983

Hydrogenation of geranylgeraniol : two pathways exist in spinach chloroplasts.

The reduction of geranylgeranylpyrophosphate to phytylpyrophosphate in spinach chloroplasts is described for the first time. The reductase is localized in the chloroplast envelope. By contrast, the reduction of the geranylgeranyl moiety in Chl synthesis is catalyzed in the thylakoids (via Chl synthetase). NADPH functions as electron donor in both reactions. Chl synthetase is firmly bound to the thylakoid membranes, and very little activity is found in the stroma fraction. Chl synthetase in chloroplasts can use the pyrophosphate ester of either phytol, geranylgeraniol, or farnesol, phytylpyrophosphate being the preferred substrate. Exogenous Chlide exhibits no influence on Chl synthesis by chloroplast subfractions.

Journal Article↗
PubMed1982

Lateral geniculate unit activity in freely moving rats. II. Relation to conditioning and motivation.

Unit activity of the lateral geniculate body was recorded on successive days using implanted semimicroelectrodes. Unit responses to light stimuli recorded in water deprived and satiated animals were compared. They differed in dependence on whether the light stimulus is a conditioned one (leading to a behavioral response) or is acting merely as a physical event without relevance to the animal’s adaptive behavior. This was confirmed using the following experimental procedures: (i) recording from one cell population on several successive days under equal conditions, (ii) elaborating a conditioned reflex during recording, and (iii) comparing unit responses to light stimuli in relation to the rat’s behavioral responses (correct, not correct) during the first training days.

Animals↗
PubMed1980

Influence of Anaerobiosis on Chlorophyll Biosynthesis in Greening Oat Seedlings (Avena sativa L.).

The influence of anaerobiosis for 0.5 to 15 hours on the last steps of chlorophyll biosynthesis of etiolated oat seedlings was investigated. Phototransformation of protochlorophyllide to chlorophyllide is only slightly reduced and esterification of chlorophyllide is slightly increased by pretreatment under anaerobic conditions. Pretreated plants accumulate the geranylgeraniol ester of chlorophyllide rather than the phytol ester. Enzymic hydrogenation of the esterifying alcohol geranylgeraniol to phytol is presumably inhibited by anaerobiosis.

Journal Article↗
PubMed1980

Detection and partial characterization of activity of chlorophyll synthetase in etioplast membranes.

The esterification of chlorophyllide a was investigated an irradiated etioplast-membrane fractions ('broken etioplasts') from oat seedlings (Avena sativa L.). As a substrate, [1(-3)H]geranylgeraniol and its monophosphate and diphosphate derivatives were prepared by chemical synthesis. Geranylgeraniol and its monphosphate derivative are incorporated into chlorophyll only in the presence of ATP whereas the diphosphate derivative is incorporated also without ATP. The yield of esterified chlorophyll is 80-90% of chlorophyllide with saturating substrate concentrations. The term 'chlorophyll synthetase' is used to describe the enzyme activity which is different from chlorophyllase. Other substrates are phytol and farnesol either with ATP or as the diphosphate derivatives. The relative specificity of 'chlorophyll synthetase' for thse substrates is geranylgeraniol:phytol:farnesol = 6:3:1. In these experiments in vitro, a new chlorphyll esterified with farnesol was detected which does not occur in intact plants. Geraniol and n-pentadecanol are no substrates for the enzyme. Protochlorphyllide which is present in non-irradiated etioplast membrane fractions is not esterified under the same conditions.

Carbon-Oxygen Ligases↗
PubMed1980

Response variations of neurons in the lateral geniculate body of the freely moving rat.

The influence of the motivational state on the discharge rate and flash evoked activity of 57 single units of the dorsal lateral geniculate body (LGB) was investigated using extracellular microelectrodes. Flashes were presented either alone (control group) or followed by water reinforcement (trained group). With decreasing thirst motivation the background activity of most of the cells of both groups changed. This change consisted mainly in a decrease of the discharge rate. After satiation two thirds of the cells exhibited response variations to light stimuli. In trained thirsty animals in 10 out of 19 cells these changes were of very high degree, as the usual response pattern consisting in a sequence of excitatory and inhibitory phases was lost. Under such conditions the light acted as a conditioned stimulus in the thirsty animal. Nonvisual stimuli preceding the flashes and evoking inhibiton of the reflex behavior in trained rats produced small response modulations in about two thirds of the cells of either animal group. The assumption is made that the motivational state of the animal or environmental stimuli not belonging to the original conditioned stimulus - unconditioned stimulus (CS-US) paradigm are less effective in producing response changes of cells to physically equal stimuli than the biological relevance of the stimulus.

Animals↗
PubMed1978

On the linkages between chromophore and protein in biliproteins, VII. Amino acid sequence in the chromophore regions of C-phycoerythrin from Pseudanabaena W 1173 and Phormidium persicinum.

Bilipeptides from all chromophore regions were prepared by trypsin digestion of C-phycoerythrin from Pseudanabaena W 1173 and Phormidium persicinum. Analytical separation and quantitative determination of bilipeptides was achieved by isoelectric focusing, preparative isolation by gel chromatography and ion-exchange chromatography. Amino acid analysis revealed cysteine as the only amino acid common to all chromopeptides. Amino acid sequences were determined by Edman degradation and the dansyl-Edman technique. Sequences are different in all 5 and 6 chromophore regions, respectively. Possible homologies are discussed. A thioether linkage between ring A of the chromophore and cysteine was found in the bilipeptides (as before in biliproteins). A second linkage (serine ester) was found in only one peptide (CM 4.I from Pseudanabaena W 1173). This peptide absorbs as cation at a longer wavelength (559 nm) than the other bilipeptides (542 - 550 nm).

Amino Acid Sequence↗
PubMed1975

The structures of the phytochrome chromophore in both photoreversible forms.

Spectral measurements of phytochrome are performed after unfolding of the peptide chain. By comparison with bile pigments of known structure, structure 1a, containing a hydrogenated ring A, is deduced for the PR chromophore. Its spectral properties indicate that the chromophore of the physiologically active PFR form has lost the double bond of the bridge joining rings A and B.

Bile Pigments↗
PubMed1975

[Plastic response changes in neurons from lateral geniculate body in rats submitted to conditional reflectory stimulation].

In alert curarized rats the influence of an electric stimulation of the tail skin on the flash-evoked activity of single units of the dorsal part of the lateral geniculate body (CGLd) was investigated. The light flashes were applied 400 msec prior to the electric shocks. 50% of the units showed a change of the response pattern to flash. In the majority of cases the response shifts consisted in a facilitation, which developed gradually and persisted in most of the units examined, even when the electrical stimulus was no longer given in combination with the light. The results are discussed taking into consideration the possibility of an altered emotional or motivational status of the animal, which could play a role in the development of plasticity at the unitary level.

Action Potentials↗