Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.12.7.2 (hydrogenase)
3,522 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The gene encoding a protein containing a putative [6Fe-6S] prismane cluster has been cloned from Desulfovibrio vulgaris (Hildenborough) and sequenced. The gene encodes a polypeptide composed of 553 amino acids (60,161 Da). The DNA-derived amino acid sequence was partly confirmed by N-terminal sequencing of the purified protein and of fragments of the protein generated by CNBr cleavage. Furthermore, the C-terminal sequence was verified by digestion with carboxypeptidases A and B. The polypeptide contains nine Cys residues. Four of these residues are gathered in a Cys-Xaa2-Cys-Xaa7-Cys-Xaa5-Cys motif located towards the N-terminus of the protein. No relevant sequence similarity was found with other proteins, including those with high-spin Fe-S clusters (nitrogenase, hydrogenase), with one significant exception: the stretch containing the first four Cys residues spans two submotifs, Cys-Xaa2-Cys and Lys-Gly-Xaa-Cys-Gly, separated by 11 residues, that are also present in high-spin Fe-S cluster containing CO dehydrogenase. Western-blot analysis demonstrates cross-reactivity of antibodies raised against the purified protein both in Desulfovibrio strains and other sulfate-reducing bacteria. Hybridization of the cloned gene with genomic DNA of several other Desulfovibrio species indicates that homologous sequences are generally present in the genus Desulfovibrio.
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PMID:The primary structure of a protein containing a putative [6Fe-6S] prismane cluster from Desulfovibrio vulgaris (Hildenborough). 133 51

The detrimental effects of excessive Ni on plant growth have been well known for many years. More recent evidence indicates that Ni is required in small amounts for normal plant growth and development. Ni is an essential component of urease in plants and microorganisms. A deficiency of Ni in plants is reported to result in necrotic lesions in leaves in response to toxic accumulations of urea. Urease plays an essential role in mobilization of nitrogenous compounds in plants, a process that is especially important during seed germination and fruit formation when protein reserves are degraded into amino acids. Arginine, an abundant amino acid in plants, when degraded produces urea as a product and urease is needed for urea utilization. Theories of urea formation during allantoin degradation in Glycine max have been recently refuted. In G. max ureides apparently are metabolized via an amidohydrolase reaction with subsequent degradation of ureidoglycine, yielding glyoxylate, NH+4 and CO2. No evidence is available for the formation of urea in this pathway. Nitrogen-fixing symbionts, such as Rhizobium and Bradyrhizobium, contain two known Ni enzymes: urease and hydrogenase. Optimum growth of nodulated legumes and actinorhizal plants may depend on an adequate supply of Ni to meet the requirements of the Ni-requiring enzymes in host plants and endophytes. The seeds of severely Ni-deficient Hordeum are completely inviable, thus providing conclusive evidence for the essentiality of Ni for this species. The evidence indicates that Ni must be added to the list of micronutrient elements generally required by plants.
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PMID:Nickel as a micronutrient element for plants. 307 27

Modern phylogenetic schemes propose a free-living turbellarian-like organism as the ancestor of all Bilateria, including chordates. While neuropeptides are now known to be of ancient origin within the nervous systems of invertebrates, the neuropeptides of turbellarians remain virtually unexplored. Here we report the primary structure of an FMRFamide-related pentapeptide, Gly-Tyr-Ile-Arg-Phe amide (GYIRFamide), isolated from an acidified ethanolic extract of the aquatic triclad turbellarian, Dugesia tigrina. Previously, we reported the primary structure, RYIRFamide, from the New Zealand terrestrial turbellarian, Artioposthia triangulata, widely regarded as a most atypical species. However, the present data implies a high degree of primary structural conservation between the FMRFamide-related peptides of both species despite the zoogeographical isolation of the New Zealand form for several hundred million years. In addition, while authentic FMRFamide itself has been identified in many molluscs and a few annelids, the current data would suggest that turbellarian analogues are typically pentapeptides with an X-Y-I-R-Famide motif. A protein/peptide database search revealed that the sequence GYIRF is contained within the primary structure of several bacterial Ni/Fe hydrogenase B-type cytochrome subunits and several proliferating cell nuclear antigens (cyclins) from plants.
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PMID:GYIRFamide: a novel FMRFamide-related peptide (FaRP) from the triclad turbellarian, Dugesia tigrina. 773 39

In order to confirm the amino acid sequence predicted from the nucleotide sequence of cDNA and also to elucidate the intracellular localization and molecular evolution, human liver alanine-glyoxylate transaminase 1 (AGT1) was purified and subjected to partial amino acid sequence determination, with special attention to posttranslational modification. The enzyme was purified to homogeneity from the 10,000 x g supernatant of human liver homogenate. The purified enzyme showed only a single protein band at about 43 kDa on SDS-PAGE, indicating that it is a homodimer of two identical subunits, because the native enzyme has a molecular mass of about 80 kDa. Both the amino- and carboxyl-terminal peptides of the enzyme were isolated from a cyanogen bromide digest of the S-carboxyl-methylated protein and subjected to amino acid sequence determination. The alpha-amino group of the amino-terminal peptide was shown to be blocked by an acetyl group. The carboxyl-terminal sequence contained a putative N-glycosylation sequence (-Asn-Ala-Thr-), the only one present in the whole molecule, but this sequence was normally determined, indicating that the enzyme is not N-glycosylated. Purdue et al. [J. Cell Biol. 111, 2341-2351 (1990)] have reported that Pro-11, Gly-170, and Ile-340 in normal human AGT1 were replaced by Leu, Arg, and Met, respectively, in a patient with primary hyperoxaluria type 1. We confirmed that residue-11 was Pro. Both the amino- and carboxyl-terminal sequences of the enzyme showed extensive similarity with those of rat liver mitochondrial serine-pyruvate aminotransferase and the small chain of hydrogenase from a thermophilic unicellular cyanobacterium, Synechococcus PCC 6716.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Purification and amino- and carboxyl-terminal amino acid sequences of alanine-glyoxylate transaminase 1 from human liver. 779 68

The effect of the Bradyrhizobium japonicum hydrogenase on nitrogen fixation was evaluated by comparing the growth of Vigna and Glycine species inoculated with a Hup mutant and its Hup revertant. In all experiments, the growth of plants inoculated with the strain without hydrogenase was at least equal to the growth of the strain with hydrogenase. For Glycine usuriensis and Glycine max cv. Hodgson in liquid culture, the growth was higher with the Hup strain. It is possible that reduced rates of nitrogen fixation in the presence of hydrogenase are due to O(2) depletion caused by the hydrogen oxidizing, since the oxygen pressure in the air appears to be a limiting factor of symbiotic nitrogen fixation in the soybean.
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PMID:Influence of the Bradyrhizobium japonicum Hydrogenase on the Growth of Glycine and Vigna Species. 1634 9

A Collection of 360 isolates of Bradyrhizobium japonicum was developed from soybean (Glycine max [L.] Merrill) nodules taken from 18 locations in Delaware. The isolates were characterized serologically with an enzyme-linked immunosorbent assay, morphologically by colony type on yeast extract-mannitol agar, and for production of rhizobitoxine symptoms with soybean plants. These analyses revealed 12 and 3 groups based on serology and morphology, respectively. The more common identifiable isolates were in serogroups 94, 6, 122, and 76. Nearly 33% of the isolates were rated nonreactive with all of the antisera tested. Overall, 18% of the isolates produced rhizobitoxine symptoms, and these were associated with five known serogroups (31, 46, 76, 94, and 130) and the nonreactive grouping, but with only one colony type. A subsample of 92 isolates was rated for N(2)-fixing ability in the greenhouse and for hydrogenase phenotype in the laboratory. The nitrogen content of plant shoots was strongly and comparably related to both the serological and morphological groupings. Rhizobitoxine and hydrogenase phenotypes were relatively poor predictors of symbiotic effectiveness. Among the serologically reactive isolates, those in serogroups 38-115, 122, and 110 fixed the most N(2), whereas one colony type (that containing isolates producing rhizobitoxine) was clearly inferior to the remaining two morphological groupings. Isolates displaying hydrogenase activity (approximately 15% of the isolates tested) correlated with three serologically reactive groupings (serogroups 110 and 122 and a 122/123 cross-reactive group) and two colony types, none of which coincided with groupings containing bradyrhizobia rated positive for rhizobitoxine production.
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PMID:Symbiotic effectiveness of indigenous soybean bradyrhizobia as related to serological, morphological, rhizobitoxine, and hydrogenase phenotypes. 1634 95

Thirty-four strains of Bradyrhizobium japonicum within serogroup 110 were examined for phenotypic diversity. The strains differed in their abilities to nodulate and fix dinitrogen with Glycine max (L.) Merr. cv. Williams. Thirteen strains expressed uptake hydrogenase activity when induced as free-living cultures in the presence of 2% hydrogen and oxygen. Six bacteriophage susceptibility reactions were observed. Each of the strains produced either a large, mucoid or a small, dry colony morphology, but colony type was not related to effectiveness for nitrogen fixation.
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PMID:Phenotypic Diversity among Strains of Bradyrhizobium japonicum Belonging to Serogroup 110. 1634 97

The ATP-dependent evolution of H(2) catalyzed by nitrogenase and the hydrogenase-catalyzed oxidation of H(2) have been implicated as factors influencing the efficiency of energy utilization in the N(2) fixation process. The effects of rhizobial strain and plant age on the H(2)-evolving and H(2)-utilizing activity of leguminous root nodules are described in this manuscript. Two classes of legume-Rhizobium combinations were observed in studies with soybeans (Glycine max L. Merr.) and cowpeas (Vigna unguiculata L. Walp.). One group evolved H(2) in air; the other group did not exhibit net evolution of H(2). The latter group metabolized H(2) formed within the nodule through the action of a hydrogenase. The capacity to oxidize H(2) was strongly linked to the strain of Rhizobium used to inoculate cowpeas and soybeans. Although the magnitude of H(2) evolution in air changed during vegetative growth of a given symbiont, the ratio of H(2) evolved in air to total nitrogenase activity was not appreciably altered during this period. No consistent difference in nitrogenase activity as measured by the C(2)H(2) reduction assay was observed between symbionts with an active hydrogenase and those that apparently lack the enzyme and evolve H(2). The effects of the two reactions of H(2) on total N(2) fixation and yield must now be established.
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PMID:Hydrogen reactions of nodulated leguminous plants: I. Effect of rhizobial strain and plant age. 1666 Jan 57

The interaction between the ATP-dependent evolution of H(2) catalyzed by nitrogenase and the oxidation of H(2) via a hydrogenase has been postulated to influence the efficiency of the N(2)-fixing process in nodulated legumes. A comparative study using soybean (Glycine max L. Merr.) cv. Anoka inoculated with either Rhizobium japonicum strain USDA 31 or USDA 110 and cowpea (Vigna unguiculata L. Walp.) cv. Whippoorwill inoculated with Rhizobium strain 176A27 or 176A28 cultured on a N-free medium was conducted to address this question. Nodules from the Anoka cultivar inoculated with USDA 31 evolved H(2) in air and the H(2) produced accounted for about 30% of the energy transferred to the nitrogenase system during the period of active N(2) fixation. In contrast the same soybean cultivar inoculated with USDA 110 produced nodules with an active hydrogenase and consequently did not evolve H(2) in air. A comparison of Anoka soybeans inoculated with the two different strains of R. japonicum showed that mean rates of C(2)H(2) reduction and O(2) consumption and mean mass of nodules taken at four times during vegetative growth were not significantly different.When compared to Anoka inoculated with USDA 31, the same cultivar inoculated with USDA 110 showed increases in total dry matter, per cent nitrogen, and total N(2) fixed of 24, 7, and 31%, respectively. Cowpeas in symbiosis with the hydrogenase-producing strain 176A28 in comparison with the same cultivar inoculated with the H(2)-evolving strain 176A27 produced increases in plant dry weight and total N(2) fixed of 11 and 15%, respectively. This apparent increase in the efficiency of N(2) fixation for nodulated legumes capable of reutilizing the H(2) evolved from nitrogenase is considered and it is concluded that provision of conclusive evidence of the role of the H(2)-recycling process in N(2)-fixing efficiency of legumes will require comparison of Rhizobium strains that are genetically identical with the exception of the presence of hydrogenase.
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PMID:Hydrogen Reactions of Nodulated Leguminous Plants: II. Effects on Dry Matter Accumulation and Nitrogen Fixation. 1666 Mar 1

Rates of respiratory CO(2) loss and nitrogenase activities of H(2) uptake-negative mutant strains and H(2) uptake-positive revertant strains of Rhizobium japonicum have been investigated. Two-dimensional gel protein patterns of bacteroids formed by inoculation of soybeans (Glycine max L.) with these two strains show that they are closely related and revealed only one obvious difference between them. On the basis of molecular weight standards, it was concluded that the missing protein spot in the H(2) uptake-negative mutant strain could be caused by a failure of the mutant to synthesize hydrogenase. Nodules formed by the H(2) uptake-negative mutant strain evolved respiratory CO(2) at a rate of about 10% higher than that of nodules formed by the H(2) uptake-positive revertant strain. During short-term experiments employed, rates of both C(2)H(2) reduction and (15)N(2) fixation varied considerably among replicate samples and no statistically significant differences between mutant and revertant strains were observed. It was observed that increasing the partial pressure of O(2) over nodules significantly decreased the proportion of nitrogenase electrons allocated to H(+).
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PMID:Respiratory and Nitrogenase Activities of Soybean Nodules Formed by Hydrogen Uptake Negative (Hup) Mutant and Revertant Strains of Rhizobium japonicum Characterized by Protein Patterns. 1666 77


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