Search results for "Histidine"
showing 10 items of 152 documents
Cloning and characterization of the histidine biosynthetic gene cluster of Streptomyces coelicolor A3(2).
1990
Abstract Biochemical and genetic data indicate that in Streptomyces coelicolor A3(2) the majority of the genes involved in the biosynthesis of histidine are clustered in a small region of the chromosome [Carere et al., Mol. Gen. Genet. 123 (1973) 219–224; Russi et al., Mol. Gen. Genet. 123 (1973) 225–232]. To investigate the structural organization and the regulation of these genes, we have constructed genomic libraries from S. coelicolor A3(2) in pUC vectors. Recombinant clones were isolated by complementation of an Escherichia coli hisBd auxotroph. A recombinant plasmid containing a 3.4-kb fragment of genomic DNA was further characterized. When cloned in the plasmid vector, pIJ699, this f…
Zebrafish Reveals Different and Conserved Features of Vertebrate Neuroglobin Gene Structure, Expression Pattern, and Ligand Binding
2004
Neuroglobin has been identified as a respiratory protein that is primarily expressed in the mammalian nervous system. Here we present the first detailed analysis of neuroglobin from a non-mammalian vertebrate, the zebrafish Danio rerio. The zebrafish neuroglobin gene reveals a mammalian-type exon-intron pattern in the coding region (B12.2, E11.0, and G7.0), plus an additional 5'-non-coding exon. Similar to the mammalian neuroglobin, the zebrafish protein displays a hexacoordinate deoxy-binding scheme. Flash photolysis kinetics show the competitive binding on the millisecond timescale of external ligands and the distal histidine, resulting in an oxygen affinity of 1 torr. Western blotting, i…
Amino acid activation in Ciona ovary and developing egg
1964
E stata studiata la attivazione di alcuni amini acidi negli ovociti nell'uovo vergine e nell'uovo fecondato diCiona intestinalis. L'andamento della attivazione della glicina e stato seguito sino alla neurulazione. Il quantitativo di amino acidi attivati e minimo nell'uovo vergine, esso aumenta rapidamente dopo la fecondazione. Durante la gastrulazione la attivazione della glicina raggiunge i valori maggiori.
Metabolomics discloses donor liver biomarkers associated with early allograft dysfunction
2014
Background & Aims Early allograft dysfunction (EAD) dramatically influences graft and patient outcome after orthotopic liver transplantation and its incidence is strongly determined by donor liver quality. Nevertheless, objective biomarkers, which can assess graft quality and anticipate organ function, are still lacking. This study aims to investigate whether there is a preoperative donor liver metabolomic biosignature associated with EAD. Methods A comprehensive metabolomic profiling of 124 donor liver biopsies collected before transplantation was performed by mass spectrometry coupled to liquid chromatography. Donor liver grafts were classified into two groups: showing EAD and immediate g…
Interaction of iron(II)-heme and artemisinin with a peptide mimic of Plasmodium falciparum HRP-II
2007
Abstract The interaction of heme or heme-artemisinin adducts (heme-art) with different peptides mimicking repeat sequences of the Histidine-Rich-Protein-II of Plasmodium falciparum (PfHRP-II) was investigated. The pseudo-first order rate constants of the coordination of heme or heme-art onto a histidine rich peptide, used as a mimic of PfHRP-II putative heme binding sequence, are of the same order of magnitude, namely 42 and 14 s −1 , respectively. Despite the intrinsic reactivity of the carbonyl at C10 of heme-art toward a hydroxyl function, a peptide containing a serine or threonine residue does not readily react with heme-art adducts. Therefore, a much higher affinity of heme-art compare…
Nature of O2, CO, and CN binding to hemoprotein models
2004
Parametrization of a molecular-mechanics program to include terms specific for five- and six-coordinate transition metal complexes results in computer-simulated structures of hemo complexes. The principal new feature peculiar to five- and six-coordination is a term that measures the effect of electron-pair repulsion modified by the ligand electronegativity and takes into account the different structural possibilities. The work consists in the modification of program molecular mechanics for penta and hexacoordination. The model system takes into account the structural differences of the fixing center in the hemoglobin subunits. The customary proximal histidine is added. The macrocycle hemo I…
Nature of FeIII–O2, FeII–CO and FeIII–CN complexes of hemoprotein models
2003
Abstract Parametrization of a molecular-mechanics program to include terms specific for 5- and 6-coordinate transition metal complexes results in computer-simulated structures of hemo complexes. The principal new feature peculiar to 5- and 6-coordination is a term that measures the effect of electron-pair repulsion modified by the ligand electronegativity and takes into account the different structural possibilities. The work consists in the modification of program molecular mechanics for 5- and 6-coordination. The model system takes into account the structural differences of the fixing centre in the haemoglobin (Hb) subunits. The customary proximal histidine is added. The macrocycle hemo I…
Cyanide binding and heme cavity conformational transitions in **Drosophila melanogaster** hexacoordinate hemoglobin
2006
The reason for the presence of hemoglobin-like molecules in insects, such as Drosophila melanogaster, that live in fully aerobic environments has yet to be determined. Heme endogenous hexacoordination (where HisE7 and HisF8 axial ligands to the heme Fe atom are both provided by the protein) is a recently discovered mechanism proposed to modulate O-2 affinity in hemoglobins from different species. Previous results have shown that D. melanogaster hemoglobin 1 (product of the glob1 gene) displays heme endogenous hexacoordination in both the ferrous and ferric states. Here we present kinetic data characterizing the exogenous cyanide ligand binding process, and the three-dimensional structure (a…
Evolutionary history of the OmpR/IIIA family of signal transduction two component systems in Lactobacillaceae and Leuconostocaceae
2011
15 pages, 3 tables, 7 figures.
Fumarate regulation of gene expression in Escherichia coli by the DcuSR (dcuSR genes) two-component regulatory system.
1998
ABSTRACT In Escherichia coli the genes encoding the anaerobic fumarate respiratory system are transcriptionally regulated by C 4 -dicarboxylates. The regulation is effected by a two-component regulatory system, DcuSR, consisting of a sensory histidine kinase (DcuS) and a response regulator (DcuR). DcuS and DcuR are encoded by the dcuSR genes (previously yjdHG ) at 93.7 min on the calculated E. coli map. Inactivation of the dcuR and dcuS genes caused the loss of C 4 -dicarboxylate-stimulated synthesis of fumarate reductase ( frdABCD genes) and of the anaerobic fumarate-succinate antiporter DcuB ( dcuB gene). DcuS is predicted to contain a large periplasmic domain as the supposed site for C 4…