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1.
A. Tyagi J. Hermans J. Steppuhn Ch. Jansson F. Vater R. G. Herrmann 《Molecular & general genetics : MGG》1987,207(2-3):288-293
Summary Several cDNA clones encoding the 33 kDa protein associated with the photosynthetic water oxidation activity of spinach were sequenced. A 1208 bp insert of one of the clones encodes the entire 331 amino acid residues of the precursor protein including 84 amino acids (8.5 kDa) of the amino-terminal transit peptide, 49 bp of the 5 and 111 bp of the 3 untranslated segment of the mRNA. The 3 poly(A) tail starts 19 bp downstream from a putative polyadenylation signal, TATAAA. The hydrophilic mature protein consists of 247 amino acid residues corresponding to an Mr of 26.5 kDa, which is 6.5 kDa smaller than the value determined by SDS-polyacrylamide gel electrophoresis (33–34 kDa), and shows a certain degree of conservation with the putative Mn-complexing active sites of bacterial Mn-dependent superoxide dismutases. The anatomy of the unusually long transit sequence is discussed with regard to current concepts of protein import into and protein routein within the organelle. 相似文献
2.
Proteinchemical and kinetic features of gramicidin S synthetase 总被引:1,自引:0,他引:1
J Vater W Schlumbohm J Salnikow K D Irrgang M Miklus T Choli H Kleinkauf 《Biological chemistry Hoppe-Seyler》1989,370(9):1013-1018
The amino-acid compositions of both enzymes of gramicidin S synthetase were determined. These proteins contain a high number of acidic amino-acid residues. Phenylalanine racemase, the light enzyme, was sequenced from the N-terminus until position 10. The kinetics of the thioester formation reactions were studied. The half-life times of these processes under substrate saturation conditions were found in the range between seconds and a few minutes. The valine activation at the heavy enzyme was detected as one of the rate-limiting steps of the biosynthesis of gramicidin S. 相似文献
3.
Formation of double-walled microtubules and multilayered tubulin sheets by basic proteins 总被引:1,自引:0,他引:1
E Unger K J B?hm H Müller H Grossman H Fenske W Vater 《European journal of cell biology》1988,46(1):98-104
Some basic proteins enable microtubule protein to form special assembly products in vitro, known as double-walled microtubules. Using histones (H1, core histones) as well as the human encephalitogenic protein to induce the formation of double-walled microtubules, we made the following electron microscopic observations: (1) Double-walled microtubules consist of an "inner" microtubule which is covered by electron-dense material, apparently formed from the basic protein, and by a second tubulin wall. (2) The tubulin of the second wall seems to be arranged as protofilaments, surrounding the inner microtubule in a helical or ring-like manner. (3) The surface of double-walled microtubules lacks the projections of microtubule-associated proteins, usually found on microtubules. (4) In the case of protofilament ribbons (incomplete microtubules), H1 binds exclusively to their convex sides that correspond to the surface of microtubules. Zn2+-induced tubulin sheets, consisting in contrast to microtubules of alternately arranged protofilaments, are covered by H1 on both surfaces. Furthermore, multilayered sheet aggregates appeared. The results indicate that the basic proteins used interact only with that protofilament side which represents the microtubule surface. In accordance with this general principle, models on the structure of double-walled microtubules and multilayered tubulin sheets were derived. 相似文献
4.
M. Vater A. S. Feng M. Betz 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1985,157(5):671-686
Summary The frequency-place map of the horseshoe bat cochlea was studied with the horseradish peroxidase (HRP) technique involving focal injections into various, physiologically defined regions of cochlear nucleus (CN). The locations of labeled spiral ganglion cells and their termination sites on inner hair cells of the organ of Corti from injections into CN-regions responsive to different frequencies were analyzed in three dimensional reconstructions of the cochlea. Horseshoe bats from different geographical populations were investigated. They emit orientation calls with constant frequency (CF) components around 77 kHz (Rhinolophus rouxi from Ceylon) and 84 kHz (Rhinolophus rouxi from India) and their auditory systems are sharply tuned to the respective CF-components.The HRP-map shows that in both populations: (i) the frequency range around the CF-component of the echolocation signal is processed in the second half-turn of the cochlea, where basilar membrane (BM) is not thickened, secondary spiral lamina (LSS) is still present and innervation density is maximal; (ii) frequencies more than 5 kHz above the CF-component are processed in the first halfturn, where the thickened BM is accompanied by LSS and innervation density is low; (iii) frequencies below the spectral content of the orientation call are represented in apical turns showing no morphological specializations. The data demonstrate that the cochlea of horseshoe bats is normalized to the frequency of the individual specific CF-component of the echolocation call.The HRP-map can account for the overrepresentation of neurons sharply tuned to the CF-signal found in the central auditory system. A comparison of the HRP-map with a map derived with the swollen nuclei technique following loud sound exposure (Bruns 1976b) reveals that the latter is shifted towards cochlear base by about 4 mm. This discrepancy warrants a new interpretation of the functional role of specialized morphological structures of the cochlea within the mechanisms giving rise to the exceptionally high frequency selectivity of the auditory system.Abbreviations
AVCN
anteroventral CN
-
BF
best frequency
-
BM
basilar membrane
-
CF
constant frequency
-
CN
cochlear nucleus
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DCN
dorsal CN
-
FM
frequency modulated
-
HRP
horseradish peroxidase
-
IHC
inner hair cell
-
LSS
secondary spiral lamina
-
OHC
outer hair cell
-
PVCN
posteroventral CN
-
RF
resting frequency
-
RRc
Rhinolophus rouxi from Ceylon
-
RRi
Rhinolophus rouxi from India 相似文献
5.
O. W. Henson Jr. G. Schuller M. Vater 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1985,157(5):587-597
Summary Cochlear microphonic (CM) and evoked neural (N-1) potentials were studied in two species of Doppler shift compensating bats with the aid of electrodes chronically implanted in the scala tympani. Potentials were recorded from animals fully recovered from the effects of anesthesia and surgery. InPteronotus p. parnellii andRhinolophus rouxi the CM amplitude showed a narrow band, high amplitude peak at a frequency about 200 Hz above the resting frequency of each species. InPteronotus the peak was 25–35 dB higher in amplitude than the general CM level below or above the frequency of the amplitude peak. InRhinolophus the amplitude peak was only a few dB above the general CM level but it was prominent because of a sharp null in a narrow band of frequencies just below the peak. The amplitude peak and the null were markedly affected by body temperature and anesthesia. InPteronotus high amplitude CM potentials were produced by resonance, and stimulated cochlear emissions were prominent inPteronotus but they were not observed inRhinolophus. InPteronotus the resonance was indicated by a CM afterpotential that occurred after brief tone pulses. The resonance was not affected by the addition of a terminal FM to the stimulus and when the ear was stimulated with broadband noise it resulted in a continual state of resonance. Rapid, 180 degree phase shifts in the CM were observed when the stimulus frequency swept through the frequency of the CM amplitude peak inPteronotus and the frequency of the CM null inRhinolophus. These data indicate marked differences in the physiological properties of the cochlea and in the mechanisms responsible for sharp tuning in these two species of bats. 相似文献
6.
A Gadow J Vater W Schlumbohm Z Palacz J Salnikow H Kleinkauf 《European journal of biochemistry》1983,132(2):229-234
The reactive thioester complexes of gramicidin S synthetase with substrate amino acids and intermediate peptides are slowly hydrolyzed in neutral buffer solutions under mild conditions. Fully active enzyme is recovered. These processes are strongly accelerated by certain thiol protective agents. In the presence of 1 mM dithioerythritol the half-life times of these hydrolysis reactions are in the range of 1-90 h at 3 degrees C. The thioester complex of gramicidin S synthetase 2 (GS2, the heavy enzyme) with the tripeptide DPhe-Pro-Val is distinguished by the highest stability of all these intermediates. A different decomposition pattern is observed for the thioester complex of GS2 with LOrn. Here 3-amino-2-piperidone (cyclo-LOrn) is formed in a rapid cyclization reaction. This product specifically blocks the activation center of GS2 for LOrn at the thioester binding site. All other activation reactions of gramicidin S synthetase are unaffected. A procedure for a specific labelling of the reaction centers of the multienzyme is outlined. 相似文献
7.
Monoclonal antibodies were raised against purified cortical secretory vesicles (CVs) from the eggs of Strongylocentrotus purpuratus. One of the monoclonal antibodies (MAb 69-10, an IgA) was shown by immunofluorescence labeling of intact and detergent-lysed CVs to be directed against a CV content antigen. Immunoblot analysis of CVs revealed that MAb 69-10 bound to a major CV polypeptide with an Mr similar to that of hyalin (i.e., 300,000). MAb 69-10 was subsequently shown to bind to purified hyalin prepared from S. purpuratus and to cross react with hyalin prepared from Lytechinus pictus. Immunogold labeling on thin sections of unfertilized S. purpuratus eggs showed that hyalin was localized to the electron-lucent portion of CVs. This result is in agreement with the labeling pattern obtained by Hylander and Summers (Dev Biol 93:368-380, 1982) using polyclonal antihyalin antibodies. In fertilized eggs and later-stage embryos, hyalin was observed to be located on the external surface of the embryo. MAb 69-10 should be useful in studies of the structure of hyalin and its function in morphogenesis. 相似文献
8.
Fluorimetric studies of the binding of d-ribulose 1,5-bisphosphate (RuP2) and the effectors 6-phosphogluconate and fructose 1,6-bisphosphate to the d-ribulose 1,5-bisphosphate carboxylase/oxygenase from spinach were correlated with the functions of these sugar phosphates in the carboxylation reaction. These agents compete for two binding sites of the enzyme. At relatively low concentrations they bind to an allosteric site, where 6-phosphogluconate and fructose 1,6-bisphosphate display their stimulating effect on the fixation of CO2. At higher concentrations these compounds inhibit the carboxylation reaction and compete with RuP2 for the reaction center of the carboxylase. Preincubation of the enzyme with low concentrations of RuP2 (0.1–5 μm) inhibits the activity of these effectors as well as the effector-induced fluorescence changes of the enzyme-2-p-toluidinonapthalene-6-sulfonate (TNS) complex by competition for the regulatory center which could be identified as the high affinity binding site of the enzyme for RuP2 with a KD = 0.6 μm. The deactivation of the carboxylase which is observed on preincubation of the enzyme with RuP2 in the absence of bicarbonate and Mg2+ cannot be correlated to the binding of RuP2 to the effector site. The deactivation process occurs in an RuP2 concentration range similar to that for CO2 fixation. 相似文献
9.
The VPS1 protein, a homolog of dynamin required for vacuolar protein sorting in Saccharomyces cerevisiae, is a GTPase with two functionally separable domains 总被引:7,自引:2,他引:5
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C A Vater C K Raymond K Ekena I Howald-Stevenson T H Stevens 《The Journal of cell biology》1992,119(4):773-786
The product of the VPS1 gene, Vps1p, is required for the sorting of soluble vacuolar proteins in the yeast Saccharomyces cerevisiae. We demonstrate here that Vps1p, which contains a consensus tripartite motif for guanine nucleotide binding, is capable of binding and hydrolyzing GTP. Vps1p is a member of a subfamily of large GTP-binding proteins whose members include the vertebrate Mx proteins, the yeast MGM1 protein, the Drosophila melanogaster shibire protein, and dynamin, a bovine brain protein that bundles microtubules in vitro. Disruption of microtubules did not affect the fidelity or kinetics of vacuolar protein sorting, indicating that Vps1p function is not dependent on microtubules. Based on mutational analyses, we propose a two-domain model for Vps1p function. When VPS1 was treated with hydroxylamine, half of all mutations isolated were found to be dominant negative with respect to vacuolar protein sorting. All of the dominant-negative mutations analyzed further mapped to the amino-terminal half of Vps1p and gave rise to full-length protein products. In contrast, recessive mutations gave rise to truncated or unstable protein products. Two large deletion mutations in VPS1 were created to further investigate Vps1p function. A mutant form of Vps1p lacking the carboxy-terminal half of the protein retained the capacity to bind GTP and did not interfere with sorting in a wild-type background. A mutant form of Vps1p lacking the entire GTP-binding domain interfered with vacuolar protein sorting in wild-type cells. We suggest that the amino-terminal domain of Vps1p provides a GTP-binding and hydrolyzing activity required for vacuolar protein sorting, and the carboxy-terminal domain mediates Vps1p association with an as yet unidentified component of the sorting apparatus. 相似文献
10.
Morphological classification of the yeast vacuolar protein sorting mutants: evidence for a prevacuolar compartment in class E vps mutants.
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C K Raymond I Howald-Stevenson C A Vater T H Stevens 《Molecular biology of the cell》1992,3(12):1389-1402
The collection of vacuolar protein sorting mutants (vps mutants) in Saccharomyces cerevisiae comprises of 41 complementation groups. The vacuoles in these mutant strains were examined using immunofluorescence microscopy. Most of the vps mutants were found to possess vacuolar morphologies that differed significantly from wild-type vacuoles. Furthermore, mutants representing independent vps complementation groups were found to share aberrant morphological features. Six distinct classes of vacuolar morphology were observed. Mutants from eight vps complementation groups were defective both for vacuolar segregation from mother cells into developing buds and for acidification of the vacuole. Another group of mutants, represented by 13 complementation groups, accumulated a novel organelle distinct from the vacuole that contained a late-Golgi protein, active vacuolar H(+)-ATPase complex, and soluble vacuolar hydrolases. We suggest that this organelle may represent an exaggerated endosome-like compartment. None of the vps mutants appeared to mislocalize significant amounts of the vacuolar membrane protein alkaline phosphatase. Quantitative immunoprecipitations of the soluble vacuolar hydrolase carboxypeptidase Y (CPY) were performed to determine the extent of the sorting defect in each vps mutant. A good correlation between morphological phenotype and the extent of the CPY sorting defect was observed. 相似文献