@article{HoppeFriedlSchaireretal.1983, author = {Hoppe, J. and Friedl, P. and Schairer, H. U. and Sebald, Walter and Meyenburg, K. von and Jorgensen, B. B.}, title = {The topology of the proton translocating F\(_0\) component of the ATP synthase from E. coli K12: studies with proteases}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62718}, year = {1983}, abstract = {The accessibility of the three F\(_0\) subunits a, b and c from the Escherichia coli Kll A TP synthase to various proteases was studied in F\(_1\)-depleted inverted membrane vesicles. Subunit b was very sensitive to all applied proteases. Chymotrypsin produced a defined fragment of mol. wt. 1S 000 which remained tightly bound to the membrane. The cleavage site was located at the C-terminal region of subunit b. Larger amounts of proteases were necessary to attack subunit a (mol. wt. 30 000). There was no detectable deavage of subunit c. It is suggested that the major hydrophilic part of subunit b extends from the membrane into the cytoplasm and is in contact with the F\(_1\) sector. The F\(_1\) sector was found to afford some protection against proteolysis oftheb subunit in vitro andin vivo. Protease digestion bad no influence on the electro-impelled H\(^+\) conduction via F\(_0\) bot ATP-dependent H\(^+\) translocation could not be reconstituted upon binding of F\(_1\)• A possible role for subunit b as a linker between catalytic events on the F\(_1\) component and the proton pathway across the membrane is discussed.}, subject = {Biochemie}, language = {en} } @article{SchairerHoppeSebaldetal.1982, author = {Schairer, H. U. and Hoppe, J. and Sebald, Walter and Friedl, P.}, title = {Topological and functional aspects of the proton conductor, F\(_0\), of the Escherichia coli ATP-synthase}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62721}, year = {1982}, abstract = {The isolated H\(^+\) conductor, F\(_0\) , of the Escherichia co1i ATP-synthase consists of three subunits, a, b, and c. H\(^+\) -permeable liposomes can be reconstit~ted with F\(_0\) and lipids; addition of F\(_1\)-ATPase reconstitutes a functional ATP-synthase. Mutants with altered or misslng F\(_0\) subunits are defective in H\(^+\) conduction. Thus, all three subunits are necessary for the expression of H\(^+\) conduction. The subunits a and b contain binding sites for F\(_1\)• Computer calculations, cross-links, membrane-permeating photo-reactive labels, and proteases were used to develop tentative structural models for the individual F\(_0\) subunits.}, subject = {Biochemie}, language = {en} } @article{SebaldFriedlSchaireretal.1982, author = {Sebald, Walter and Friedl, P. and Schairer, H. U. and Hoppe, J.}, title = {Structure and genetics of the H\(^+\)-conducting F\(_0\) portion of the ATP synthase}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62733}, year = {1982}, abstract = {The ATP synthase occurs in remarkably conserved form in procaryotic and eucaryotic cells. Thus, our present knowledge of ATP synthase is derived from sturlies of the enzyme from different organisms, each affering specific experimental possibilities. In recent tim es, research on the H\(^+\) -conducting F0 part of the ATP synthase has been greatly stimulated by two developments in the Escherichio coli system. Firstly, the purification and reconstitution of the whole ATP synthase as weil as the proton conductor Fa from E. coli have been achieved. These functionally active preparations are well defined in terms of subunit composition, similar to the thermophilic enzyme from PS-3 studied by Kagawa's group.u Secondly, the genetics and the molecular cloning of the genes of all the F\(_0\) subunits from E. coli yielded information on the function of subunit polypeptides and essential amino acid residues. Furthermore, the amino acid sequence of hydrophobic F\(_0\) subunits, which are difficult to analyze by protein-chemical techniques, could be derived from the nucleotide sequence of the genes. These achievements, which shall be briefly summarized in the next part of this communication, provide the framework to study specific aspects of the structure and function of the F\(_0\) subunits.}, subject = {Biochemie}, language = {en} } @article{ViebrockPerzSebald1982, author = {Viebrock, A. and Perz, A. and Sebald, Walter}, title = {The imported preprotein of the proteolipid subunit of the mitochondrial ATP synthase from Neurospora crassa. Molecular cloning and sequencing of the mRNA}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62742}, year = {1982}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{WernerSebald1981, author = {Werner, S. and Sebald, Werner}, title = {Immunological techniques for studies on the biogenesis of mitochondrial membrane proteins}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-82044}, year = {1981}, abstract = {no abstract available}, subject = {Biochemie}, language = {en} } @article{HoppeSebald1980, author = {Hoppe, J. and Sebald, Walter}, title = {Amino acid sequence of the proteolipid subunit of the proton-translocating ATPase complex from the thermophilic bacterium PS-3}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62754}, year = {1980}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{HoppeSchairerSebald1980, author = {Hoppe, J. and Schairer, H. U. and Sebald, Walter}, title = {The proteolipid of a mutant ATPase from Escherichia coli defective in H\(^+\)-conduction contains a glycine instead of the carbodiimide-reactive aspartyl residue}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62769}, year = {1980}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{HoppeSchairerSebald1980, author = {Hoppe, J. and Schairer, HU and Sebald, Walter}, title = {Identification of amino-acid substitutions in the proteolipid subunit of the ATP synthase from dicyclohexylcarbodiimide-resistant mutants of Escherichia coli}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47374}, year = {1980}, abstract = {The amino acid sequence of the proteolipid subunit of the A TP synthase was analyzed in six mutant strains from Escherichia coli K 12, selected for their increased resistance towards the inhibitor N,N'-dicyclohexylcarbodiimide. All six inhibitor-resistant mutants were found to be altered at the same position of the proteolipid, namely at the isoleucine at residue 28. Two substitutions could be identified. In type I this residue was substituted by a valine resulting in a moderate decrease in sensitivity to dicyclohexylcarbodiimide. Type II contained a threonine residue at this position. Here a strong resistance was observed. These two amino acid substitutions did not influence functional properties of the ATPase complex. ATPase as well as A TP-dependent proton-translocating activities of mutant membranes were indistinguishable from the wild type. At elevated concentrations, dicyclohexylcarbodiimide still bound specifically to the aspartic acid at residue 61 of the mutant proteolipid as in the wild type, and thereby inhibited the activity of the ATPase complex. It is suggested that the residue 28 substituted in the resistant mutants interacts with dicyclohexylcarbodiimide during the reactions leading to the covalent attachment of the inhibitor to the aspartic acid at residue 61. This could indicate that these two residues are in close vicinity and would thus provide a first hint on the functional conformation of the proteolipid. Its polypeptide chain would have to fold back to bring together these two residues separated by a segment of 32 residues.}, subject = {Biochemie}, language = {en} } @article{vonJagowSebald1980, author = {von Jagow, Gerhard and Sebald, Walter}, title = {b-Type cytochromes}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47383}, year = {1980}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{SebaldWachterTzagoloff1979, author = {Sebald, Walter and Wachter, E. and Tzagoloff, A.}, title = {Identification of amino acid substitutions in the dicyclohexylcarbodiimide-binding subunit of the mitochondrial ATPase complex from oligomycin-resistant mutants of Saccharomyces cerevisiae}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62770}, year = {1979}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{MichelWachterSebald1979, author = {Michel, R. and Wachter, E. and Sebald, Walter}, title = {Synthesis of a larger precursor for the proteolipid subunit of the mitochondrial ATPase complex of Neurospora crassa in a cell-free wheat germ system}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62789}, year = {1979}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{SebaldGrafLukins1979, author = {Sebald, Walter and Graf, T. and Lukins, H. B.}, title = {The dicyclohexylcarbodiimide-binding protein of the mitochondrial ATPase complex from Neurospora crassa and Saccharomyces cerevisiae. Identification and isolation}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62792}, year = {1979}, abstract = {Incubation of mitochondria from Neuraspara crassa and Saccharomyces cerevisiae with the radioactive ATPase inhibitor [14C]dicyclohexylcarbodiimide results in the irreversible and rather specific labelling of a low-molecular-weight polypeptide. This dicyclohexylcarbodiimide-binding protein is identical with the smallest subunit (Mr 8000) of the mitochondrial ATPase complex, and it occurs as oligomer, probably as hexamer, in the enzyme protein. The dicyclohexylcarbodiimide-binding protein is extracted from whole mitochondria with neutral chloroformjmethanol both in the free and in the inhibitor-modified form. In Neuraspara and yeast, this extraction is highly selective and the protein is obtained in homogeneaus form when the mitochondria have been prewashed with certain organic solvents. The bound dicyclohexylcarbodiimide Iabel is enriched in the purified protein up to 50-fold compared to whole mitochondria. Based on the amino acid analysis, the dicyclohexylcarbodiimide-binding protein from Neurospora and yeast consists of at least 81 and 76 residues, respectively. The content of hydrophobic residues is extremely high. Histidine and tryptophan are absent. The N-terminal ~mino acid is tyrosine in Neuraspara and formylmethionine in yeast.}, subject = {Biochemie}, language = {en} } @article{TzagoloffMacinoSebald1979, author = {Tzagoloff, A. and Macino, G. and Sebald, Walter}, title = {Mitochondrial genes and translation products}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47408}, year = {1979}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{SebaldWernerWeiss1979, author = {Sebald, Walter and Werner, S and Weiss, H}, title = {Biogenesis of mitochondrial membrane proteins in Neurospora crassa}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-82055}, year = {1979}, abstract = {no abstract available}, subject = {Biochemie}, language = {en} } @article{SebaldWild1979, author = {Sebald, Walter and Wild, G.}, title = {Mitochondrial ATPase complex from Neurospora crassa}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-82065}, year = {1979}, abstract = {The A TPase eomplex has been isolated from mitoehondria of N eurospora crassa by immunologieal teehniques. The protein ean be obtained rapidly and qua ntitatively in high purity by miero- or large-seale immunopreeipitation. Immunopreeipitation has been applied to labeled and doubly labeled mitoehondrial proteins in order to investigate the number and moleeular weights of subunit polypeptides , the site of synthesis of subunit polypeptides, and the dieycIohexyIcarbodiimide-binding protein . The A TPase complex obtained by large-seale immunopreeipitation has been used as starting ma terial for the isolation of hydrophobie polypeptides.}, subject = {Biochemie}, language = {en} } @article{SebaldNeupertWeiss1979, author = {Sebald, Walter and Neupert, W. and Weiss, H.}, title = {Preparation of Neurospora crassa mitochondria}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-82070}, year = {1979}, abstract = {The fungus Neurospora crassa represents a eukaryotic cell with high biosynthetic activities. Cell mass doubles in 2-4 hr during expone ntial growth , even in simple salt media with sucrose as the sole carbon source. The microorgani sm forms a mycelium of long hyphae durlng vegetative growth . The mitochondria can be isolated under relatively gentle condi tions since a few breaks in the threadlike hyphae are sufficient to cause the outflow of the organelles. This article describes two methods for the physical disruption of the hyphae : (I) The cell s are opened in a grind mill between two rotating corundum di sks. This is a continuous and fast procedure and allows large- and small-scale preparations of mitochondria. (2) Hyphae are ground with sand in a mortar and pestle. This procedure can be applied to microscale preparations of mitochondria starting with minute amounts of cells. Other procedures for the isolation of Neurospora mitochondria after the physical di sruption or the enzymatic degradation of the cell wall have been described elsewhere}, subject = {Biochemie}, language = {en} } @article{GrafSebald1978, author = {Graf, T. and Sebald, Walter}, title = {The dicyclohexylcarbodiimide-binding protein of the mitochondrial ATPase complex from beef heart. Isolation and amino acid composition}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62806}, year = {1978}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{WeissSebald1978, author = {Weiss, H. and Sebald, Walter}, title = {Purification of cytochrome oxidase from Neurospora crassa and other sources}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-82082}, year = {1978}, abstract = {A chromatographic procedure 1 is described by means of which cytochrome oxidase has been purified from a variety of organisms including the fungus N eurospora crassa,2,3 the unicellular alga Po/ytoma mirum, 4 the insect Locusta migratoria ,5 the frog Xenopus muel/eri,4 and the mammal Rattus norwegicus. 4 This procedure can be used to equal effect for large-scale preparations, starting from grams of mitochondrial protein, or for small-scale preparations starting from milligrams. The cytochrome oxidase preparations from the different organisms are enzymically active. They show similar subunit compositions.}, subject = {Biochemie}, language = {en} } @article{Sebald1977, author = {Sebald, Walter}, title = {Biogenesis of mitochondrial ATPase}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47362}, year = {1977}, abstract = {No abstract available}, subject = {Biochemie}, language = {en} } @article{JacklSebald1975, author = {Jackl, G. and Sebald, Walter}, title = {Identification of two products of mitochondrial protein synthesis associated with mitochondrial adenosine triphosphatase from Neurospora crassa}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62812}, year = {1975}, abstract = {Soluble mitochondrial ATPase (F1) isolated from Neurospora crassa is resolved by dodecylsulfate- gel electrophoresis into five polypeptide bands with apparent molecular weights of 59000, 55000, 36000, 15000 and 12000. At least nine further polypeptides remain associated with ATPase after disintegration of mitochondria with Triton X-100 as shown by the analysis of an immunoprecipitate obtained with antiserum to F 1 A TPase. Two of the associated polypeptides with apparent molecular weights of 19000 and 11000 are translated on mitochondrial ribosomes, as demonstrated by incorporation in vivo of radioactive leueine in the presence of specific inhibitors of mitochondrial (chloramphenicol) and extramitochondrial ( cycloheximide) protein synthesis. The appearance of mitochondrial translation products in the immunoprecipitated A TPase complex is inhibited by' cycloheximide. The same applies for some of the extramitochondrial translation products in the presence of chloramphenicol. This suggests that both types of polypeptides are necessary for the assembly of the A TPase complex.}, subject = {Biochemie}, language = {en} }