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51.
52.
Cloning and sequencing of the genes encoding the large and the small subunits of the H2 uptake hydrogenase (hup) of Rhodobacter capsulatus 总被引:12,自引:0,他引:12
Michèle Leclerc Annette Colbeau Béatrice Cauvin Paulette M. Vignais 《Molecular & general genetics : MGG》1988,214(1):97-107
Summary The structural genes (hup) of the H2 uptake hydrogenase of Rhodobacter capsulatus were isolated from a cosmid gene library of R. capsulatus DNA by hybridization with the structural genes of the H2 uptake hydrogenase of Bradyrhizobium japonicum. The R. capsulatus genes were localized on a 3.5 kb HindIII fragment. The fragment, cloned onto plasmid pAC76, restored hydrogenase activity and autotrophic growth of the R. capsulatus mutant JP91, deficient in hydrogenase activity (Hup-). The nucleotide sequence, determined by the dideoxy chain termination method, revealed the presence of two open reading frames. The gene encoding the large subunit of hydrogenase (hupL) was identified from the size of its protein product (68108 dalton) and by alignment with the NH2 amino acid protein sequence determined by Edman degradation. Upstream and separated from the large subunit by only three nucleotides was a gene encoding a 34 256 dalton polypeptide. Its amino acid sequence showed 80% identity with the small subunit of the hydrogenase of B. japonicum. The gene was identified as the structural gene of the small subunit of R. capsulatus hydrogenase (hupS). The R. capsulatus hydrogenase also showed homology, but to a lesser extent, with the hydrogenase of Desulfovibrio baculatus and D. gigas. In the R. capsulatus hydrogenase the Cys residues, (13 in the small subunit and 12 in the large subunit) were not arranged in the typical configuration found in [4Fe–4S] ferredoxins. 相似文献
53.
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55.
Summary Phenotypic analyses of genetic combinations involving the gene extramacrochaetae (emc) reveal its participation in the differentiation of both sensory elements and wing veins. The study of near-amorphic alleles of emc in mitotitc recombination clones indicates that it also affects cell proliferation. These clones show abnormal sizes, shapes and spatial distribution. They differentiate extra sensory elements as well as extra veins. A gain of function mutation in the gene causes opposite phenotypes in both differentiation systems. The effects of the mutant on proliferation and patterning are consistent with the emc gene being involved in the transfer of information between neighbouring cells, which leads to the spatial expression of the achaetescute gene complex and genes involved in vein formation. 相似文献
56.
Stefan Jansson Eran Pichersky Roberto Bassi Beverley R. Green Masahiko Ikeuchi Anastasios Melis David J. Simpson Michael Spangfort L. Andrew Staehelin J. Philip Thornber 《Plant Molecular Biology Reporter》1992,10(3):242-253
We propose a nomenclature for the genes encoding the chlorophylla/b-binding proteins of the light-harvesting complexes of photosystem I and II. The genes encoding LHC I and LHC II polypeptides
are namedLhca1 throughLhca4 andLhcb1 throughLhcb6, respectively. The proposal follows the general format recommended by the Commision on Plant Gene Nomenclature. We also present
a table for the conversion of old gene names to the new nomenclature. 相似文献
57.
Summary In bacteria 5-aminolevulinate, the universal precursor in the biosynthesis of the porphyrin nucleus of hemes, chlorophylls and bilins is synthesised by two different pathways: in non-sulphur purple bacteria (Rhodobacter) or Rhizobium 5-aminolevulinate synthase condenses glycine and succinyl-CoA into 5-aminolevulinate as is the case in mammalian cells and yeast. In cyanobacteria, green and purple sulphur bacteria, as in chloroplasts of higher plants and algae a three step pathway converts glutamate into 5-aminolevulinate. The last step is the conversion of glutamate 1-semialdehyde into 5-aminolevulinate. Using a cDNA clone encoding glutamate 1-semialdehyde aminotransferase from barley, genes for this enzyme were cloned from Synechococcus PCC6301 and Escherichia coli and sequenced. The popC gene of E. coli, previously considered to encode 5-aminolevulinate synthase, appears to be a structural gene for glutamate 1-semialdehyde aminotransferase. Domains with identical amino acid sequences comprise 48% of the primary structure of the barley, cyanobacterial and putative E. coli glutamate 1-semialdehyde aminotransferases. The cyanobacterial and barley enzymes share 72% identical residues. The peptide containing a likely pyridoxamine phosphate binding lysine is conserved in all three protein sequences. 相似文献
58.
Summary Genetic recombination in Escherichia coli was investigated by measuring the effect of mutations in ruv and rec genes on F-prime transfer and mobilization of nonconjugative plasmids. Mutation of ruv was found to reduce the recovery of F-prime transconjugants in crosses with recB recC sbcA strains by about 30-fold and with recB recC sbcB sbcC strains by more than 300-fold. Conjugative plasmids lacking any significant homology with the chromosome were transferred normally to these ruv mutants. Mobilization of the plasmid cloning vectors pHSG415, pBR322, pACYC184 and pUC18 were reduced by 20- to 100-fold in crosses with ruv rec
+
sbc
+ strains, depending on the plasmid used. Recombinant plasmids carrying ruv
+ were transferred efficiently. With both F-prime transfer and F-prime cointegrate mobilization, the effect of ruv was suppressed by inactivating recA. It is proposed that the failure to recover transconjugants in ruv recA
+strains is due to abortive recombination and that the ruv genes define activities which function late in recombination to help convert recombination intermediates into viable products. 相似文献
59.
Pathogenesis-related protein 4 is structurally homologous to the carboxy-terminal domains of hevein, Win-1 and Win-2 总被引:5,自引:0,他引:5
Leslie Friedrich Mary Moyer Eric Ward John Ryals 《Molecular & general genetics : MGG》1991,230(1-2):113-119
Summary The extracellular, acidic pathogenesis-related protein, PR-4, was purified to homogeneity from leaves of Nicotiana tabacum infected with tobacco mosaic virus (TMV) and characterized by partial amino acid sequencing. Complementary DNA clones encoding PR-4 were isolated using an oligonucleotide probe based on the sequence of one of the peptides. The deduced PR-4 protein sequence was found to be related to a family of proteins including hevein and Win-1, which have an amino-terminal lectin domain and a carboxy-terminal domain of unknown function. PR-4 is homologous to the carboxy-terminus of these proteins but does not contain the lectin domain. Thus, the organization of the PR-4 family of proteins is similar to that of the plant chitinase family, in that both contain structural subclasses characterized by the presence or absence of an amino-terminal lectin domain. This observation is consistent with the proposal that the DNA encoding the lectin domain may be capable of transposing to form new genes encoding proteins of more complex, multi-domain structure. The expression of PR-4 mRNA was found to increase dramatically in response to TMV infection and the time course of RNA accumulation was similar to that of other PR proteins. 相似文献
60.
Fabrizio Arigoni P. Alexandre Kaminski Hauke Hennecke Claudine Elmerich 《Molecular & general genetics : MGG》1991,225(3):514-520
Summary The nucleotide sequence of a 4.1 kb DNA fragment containing the fixABC region of Azorhizobium caulinodans was established. The three gene products were very similar to the corresponding polypeptides of Rhizobium meliloti. The C-terminal domains of both fixB products displayed a high degree of similarity with the -subunits of rat and human electron transfer flavoproteins, suggesting a role for the FixB protein in a redox reaction. Two open reading frames (ORF) were found downstream of fixC. The first ORF was identified as fixX on the basis of sequence homology with fixX from several Rhizobium and Bradyrhizobium strains. The second ORF potentially encoded a 69 amino acid product and was found to be homologous to a DNA region in the Rhodobacter capsulatus nif cluster I. Insertion mutagenesis of the A. caulinodans fixX gene conferred a Nif– phenotype to bacteria grown in the free-living state and a Fix– phenotype in symbiotic association with the host plant Sesbania rostrata. A crude extract from the fixX mutant had no nitrogenase activity. Furthermore, data presented in this paper also indicate that the previously identified nifO gene located upstream of fixA was probably a homologue of the nifW gene of Klebsiella pneumoniae and Azotobacter vinelandii. 相似文献