Search PubMed⌕ Search

Biomedical subjects

T Hase

Publications and source records attributed to T Hase.

At least 235 records · Page 13Linked to original sources
PubMed1978

Amino acid sequence of a ferredoxin from Chlorobium thiosulfatophilum strain Tassajara, a photosynthetic green sulfur bacterium.

We have determined the amino acid sequence of a ferredoxin from a photosynthetic green sulfur bacterium, Chlorobium thiosulfatophilum strain Tassajara. It contains 61 amino acid residues with 9 cysteines, and 8 of the 9 were located at positions corresponding to those in clostridial-type ferredoxins. Other structural features were closer to those of ferredoxins from another photosynthetic bacterium, C. limicola, than to those of non-photosynthetic bacteria. Compared with ferredoxin from Chromatium, a photosynthetic purple sulfur bacterium, all photosynthetic bacterial ferredoxins have a common region in the carboxyl-terminal half with several extra residues and a unique cysteine residue. We compared all the photosynthetic bacterial ferredoxins that have been sequenced and concluded that C. thiosulfatophilum ferredoxin is most closely related to C. limicola ferredoxin I.

Amino Acid Sequence↗
PubMed1978

Complete amino acid sequence of Halobacterium halobium ferredoxin containing an Nepsilon-acetyllysine residue.

1. The complete amino acid sequence of the 2Fe-2S ferredoxin from Halobacterium halobium was determined to be: (formula see text):2. The apoferredoxin chain consists of 128 amino acid residues and has a molecular weight of 14,330. 3. There are only four cysteines in this ferredoxin molecule; they should be involved in the binding of the two iron atoms at the active center. Ther relative positions of these cysteines are similar to those of the cysteines in chloroplast ferredoxins. 4. There is a high degree of homology between H. halobium ferredoxin and chloroplast ferredoxins, though the latter molecules contain only about 98 amino acid residues. 5. H. halobium ferredoxin contains a single residue of Nepsilon-acetyllysine.

Amino Acid Sequence↗
PubMed1978

Disulfide bonds of purothionine, a lethal toxin for yeasts.

Purothionin isolated from commercial wheat flour contained several components and two of them (A-I and A-II) were isolated in pure form by CM-52 column chromatography. Each component contained 45 amino acid residues with a 4 disulfide bonds. Purothionin A-II was digested with trypsin and thermolysin to isolate cystine peptides. These were separated and purified by chromatography on an SP-Sephadex column, and paper electrophoresis and chromatography. A peptide containing a -Cys-Cys- sequence was hydrolyzed with 10 N sulfuric acid. Amino acid compositions and partial sequence studies of the cystine peptides and their performic acid-oxidized peptides revealed the positions of all 4 disulfide bonds in purothionin A-II. They were formed between residues 3 and 39, 4 and 31, 12 and 29, and 16 and 25. The results of a partial study of purothionin A-I are also presented.

Amino Acid Sequence↗
PubMed1978

Crystallization and a 5 A X-ray diffraction study of Aphanothece sacrum ferredoxin.

A chloroplast-type ferredoxin containing two non-heme iron and two labile sulfur atoms per molecule was prepared from Aphanothece sacrum. Crystals were obtained by dialysis against 75% saturated a-monium sulfate solution, and belong to the tetragonal system with cell dimensions a = b = 92.2 A and c = 47.6 A, containing four molecules in an asymmetric unit. The electron density map at 5 A resolution was calculated by using the best phase angles determined by the single isomorphous replacement method coupled with the anomalous dispersion effect. An anomalous dispersion difference Fourier map for the native crystal clearly showed four humps corresponding to the iron atoms in an asymmetric unit. The electron densis surface.

Binding Sites↗
PubMed1978

Stylostome formation by Leptotrombidium mites (Acari: Trombiculidae).

The modes of stylostome formation by larvae (chiggers) of Leptotrombidium intermedium, L. fletcheri, L. arenicola, and L. deliense in parasitized mouse skin were studied histologically in relation to their capacity to transmit Rickettsia tsutsugamushi. Three types of stylostome formation were recognized among the different species: the epidermal stylostome formed by the larva of L. intermedium; the mesenchymal stylostome formed by the larva of L. fletcheri; and, the mixed stylostome formed by the larva of both L. arenicola and L. deliense. Dermal inflammations related to the three types of stylostomes were histologically defined. The possible importance of stylostome characteristics to the transmission of rickettsial organisms is discussed.

Animals↗
PubMed1977

Amino acid sequence of chromatium vinosum ferredoxin: revisions.

Reexamination of the amino acid sequence of chromatium vinosum ferredoxin revealed that the original sequence proposed in 1970 (I) should be revised. Two segments in the sequence, residues 50-52 and residues 53-57, should be mutually displaced and therefore, the correct sequence in this region is concluded to be -Val-Glu-Val-Cys-Pro-Val-Asp-Cys-(residues 50-57). Another correction was the addition of one isoleucine residue between residues 57 and 58 and therefore, the total number of residues should be 82 instead of 81 originally counted. Sequence studies of other portions confirmed the previous results.

Amino Acid Sequence↗
PubMed1977

Horsetail (Equisetum telmateia) ferredoxins I and II. Amino acid sequences.

Two ferredoxins were isolated from horsetail (Equisetum telmateia) and their amino acid sequences were determined by use of a sequence analyzer in combination with carboxypeptidase digestion and manual Edman degradation of tryptic peptides of carboxymethyl-ferredoxins. Ferredoxins I and II each had only four cysteine residues in a total of 95 and 93 residues, respectively. The amino-terminal residues of both ferredoxins were heterogeneous, but alanine was concluded to be their genuine terminal residue. The comparison of these isozymelike molecules showed 29 differences in amino acid residues with three inverted replacements. One gap was inserted in ferredoxin II at position 32 to align the ferredoxins with greatest homology. Despite the many differences in amino acid residues there was no difference in net charges of the two ferredoxins.

Amino Acid Sequence↗
PubMed1977

Horsetail (Equisetum arvense) ferredoxins I and II Amino acid sequences and gene duplication.

Amino acid sequences of two ferredoxins isolated from Equisetum arvense were determined by conventional procedures. Ferredoxins I and II of E. arvense had 95 and 93 residues, respectively, and nearly identical sequences each with only one amino acid difference from ferredoxins. I and II of E. telmateia (1). The overall structural characteristics of these two ferredoxins were therefore very similar to those of E. telmateia ferredoxins. Ferredoxins I and II from E. arvense differ in 31 sites and those from E. telmateia in 29 sites from each other. These facts suggested that duplication of the ferredoxin gene in one organism occurred at an early evolutionary stage long before the divergence of the two horsetail species. The number of differences in amino acids between horsetail ferredoxins and other chloroplast-type ferredoxins indicated that the duplication occurred after divergence of horsetails from other plants. Comparing green plant ferredoxins, it was estimated that this gene duplication occurred about 250 million years ago. Some comments on the unique amino acid substitutions in horsetail ferredoxins are also presented.

Amino Acid Sequence↗
PubMed1976

Amino acid sequence of a four-iron-four-sulphur ferredoxin isolated from Bacillus stearothermophilus.

1. The primary structure of a 4Fe-4S ferredoxin from Bacillus stearothermophilus was determined and shown to consist of a single polypeptide chain of 81 amino acid residues. The molecular weight of the holoprotein is about 9120. 2. There are only four cysteine residues in the molecule; three of these are located near the N-terminus as a Cys-X-X-Cys-X-X-Cys segment, and the fourth cysteine residue is followed by a proline and located in the C-terminal half. 3. The Fe-S chromophore in B. stearothermophilus ferredoxin was previously well characterized and was shown to consist of a single 4Fe-4S cluster. This ferredoxin sequence establishes for the first time the relative location of the four cysteine residues necessary to bind the 4Fe-4S cluster of a 4Fe ferredoxin, and is in agreement with the criteria for the relative positions of the cysteines proposed from X-ray-crystallographic studies on an 8Fe (two 4Fe-4S clusters) ferredoxin. 4. The sequence of B. stearothermophilus ferredoxin is homologous in many segments to that of other bacterial ferredoxins, the degree of homology being greater towards ferredoxins from Desulfovibrio gigas and photosynthetic bacteria than to Clostridial ferredoxins. 5. The presence of a relatively higher number of glutamic acid and lower number of cysteine residues in the molecule may explain the greater thermal stability and oxygen-insenstivity of this ferredoxin.

Amino Acid Sequence↗
PubMed1976

Amino acid sequence of the major component of Aphanothece sacrum ferredoxin.

The amino acid sequence of the major ferredoxin component isolated from a blue-green alga, Aphanothece sacrum, has been fully determined. Chymotryptic and tryptic peptides of carboxymethyl-ferredoxin and chymotryptic peptides of oxidized ferredoxin were prepared and their sequences were analyzed...

Amino Acid Sequence↗
PubMed1976

Amino acid sequence of the major component of Nostoc muscorum ferredoxin.

The amino acid sequence of the major component of ferredoxin isolated from a blue-green alga, Nostoc muscorum, grown under N2 as the sole nitrogen source has been studied. The use of a combination of sequence analyzer, carboxypeptidases, and manual Edman degradations on tryptic and chymotryptic peptides of carboxymethylferredoxin has established the amino acid seuqence, which consists of 98 amino acid residues. Only four cysteine residues were present, located at positions 41, 46, 49, and 79. These residues must fulfil the minimum requirement in this ferredoxin for the chelation of two iron atoms, as postulated previously. The sequence is similar to those of Spirulina ferredoxins in having two extra residues at positions 10 and 14 compared with other chloroplast-type ferredoxins. Sequence comparison among blue-green algal ferredoxins suggests that Nostoc muscorum ferredoxin is more closely related to Spirulina ferredoxins than to Aphanothece major ferredoxin.

Amino Acid Sequence↗
PubMed1975

Significance of gastric secretory changes in the pathogenesis of stress ulcers.

Analyses of gastric juice withdrawn 3 hours after the pylorus was ligated and of plasma corticosterone and blood glucose after animals were exposed to rotational stress revealed that gastric secretion was highest in controls, intermediate in stressed rats that developed ulcers, and lowest in stressed rats that did not develop ulcers. Neither high nor low gastric secretion correlated with stress-ulcer formation. When initial mucosal ischemia and secretory inhibition, which occurred in all stressed rats, were considered, those that developed ulcers manifested gastric hypersecretion when compared with those that did not develop ulcers. The pathogenetic significance of gastric hypersecretion in stress-ulcer formation is discussed and correlated with mucosal microvascular changes during stress. Mean plasma corticosterone was highest in stressed rats that developed ulcers, next highest in stressed rats that did not develop ulcers, and lowest in control rats. Compared with normal rats, mean blood glucose was lowest in stressed rats and highest in controls. Hypoglycemic changes were more marked in stressed rats that developed ulcers than in stressed rats that did not develop ulcers.

Animals↗
PubMed1975

A minor component of ferredoxin from Aphanothece sacrum cells.

About 20% of the total extractable ferredoxin from a blue-green alga, Aphanothece sacrum, was separated as a minor component on a DEAE-cellulose column during the preparation of the major component of the cells. It was always found in cells collected in three different seasons. The chemical properties of the minor component was different from those of the major one. The enzymatic activity and spectral properties were those of typical chloroplast-type ferredoxins. The significance of isozymes in ferredoxin is discussed.

Amino Acids↗
PubMed1975

Evolutionary information involved in primary structures of chloroplast-type ferredoxins.

The complete amino acid sequence of a chloroplast-type ferredoxin from a fresh water prokaryote, Aphanothece sacrum, was determined. The sequence consisted of 96 amino acid residues and was homologous to those of ferredoxins of higher plants. Comparison of eight ferredoxins, including one from a green alga and three from blue-green algae, suggested that the sequences of algal ferredoxins were as different from one another as from those of higher plants. The relationship between the numbers of differences in amino acids and the period since separation from a common ancestor was not linear, even after correction for multiple substitution at an amino acid site in the sequence. It is very likely that the ferredoxins of angiosperms evolved rather rapidly and that those of algae, and particularly blue-green algae evolved rather slowly in the evolutionary scale. Several possible mechanisms of evolution of plants are discussed.

Amino Acid Sequence↗