Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q9UIJ5 (Rec)
 58,342 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A prokaryotic expression vector containing the rec A promoter and a translational enhancer element from the gene 10 leader of bacteriophage T7 was used to direct efficient synthesis of rat intestinal fatty acid binding protein (I-FABP) in E. coli. Expression of I-FABP in E. coli has no apparent, deleterious effects on the organism. High levels of expression of I-FABP mRNA in supE+ strains of E. coli, such as JM101, is associated with suppression of termination at its UGA stop codon. This can be eliminated by using a supE-strain as MG1655 and by site-directed mutagenesis of the cDNA to create an in frame UAA stop codon. E. coli-derived rat I-FABP lacks its initiator Met residues. It has been crystallized with and without bound palmitate. High resolution x-ray crystallographic studies of the 131 residue apo- and holo-proteins have revealed the following. I-FABP contains 10 anti-parallel beta-strands organized into two orthogonally situated beta-sheets. The overall conformation of the protein resembles that of a clam--hence the term beta-clam. The bound ligand is located in the interior of the protein. Its carboxylate group forms part of a unique five member hydrogen bonding network consisting of two ordered solvent molecules as well as the side chains of Arg106 and Gln115. The hydrocarbon chain of the bound C16:0 fatty acid has a distinctive bent conformation with a slight left-handed helical twist. This conformation is maintained by interactions with the side chains of a number of hydrophobic and aromatic amino acids. Apo-I-FABP has a similar overall conformation to holo-I-FABP indicating that the beta-clam structure is stable even without bound ligand. The space occupied by bound ligand in the core of the holo-protein is occupied by additional ordered solvent molecules in the apo-protein. Differences in the side chain orientations of several residues located over a potential opening to the cores of the apo- and holo-proteins suggest that solvent may play an important role in the binding mechanism.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Expression of rat intestinal fatty acid binding protein in E. coli and its subsequent structural analysis: a model system for studying the molecular details of fatty acid-protein interaction. 226 73

The present peroxidase-antiperoxidase immunohistochemical study demonstrated that approximately 50% of the total chromaffin cells of the rat adrenal medulla exhibited NPY-like immunoreactivity. The immunoreactive material was localized in the core of the chromaffin granules as well as diffusely in the cytoplasm. By combination of immunohistochemistry with noradrenaline-fluorescence microscopy, all NPY-immunoreactive chromaffin cells are nonfluorescent, indicating that all NPY-chromaffin cells co-store adrenaline. A comparison of two consecutive sections, each of which was processed for the immunostaining with anti-NPY and anti-Met-Enk-Arg-Gly-Leu antisera, respectively, indicated that NPY and preproenkephalin A and its derivatives coexist in approximately one-fifth of the total NPY-immunoreactive cells. In addition to the NPY-immunoreactive cells, a plexus of NPY-immunoreactive nerve fibers with varicosities was found in the subcapsular regions of the adrenal gland. The nerve fibers were often associated with small blood vessels and extended into the zona glomerulosa. Single NPY-immunoreactive fibers were sparsely distributed in the deeper regions of the cortex and in the medulla. Ganglion cells in the adrenal gland were not seen exhibiting intensely positive NPY-like immunoreactivity. The NPY-immunoreactive nerve fibers contained abundant small clear vesicles mixed with a few small and large granular vesicles. The immunoreactive material appeared on the granular cores as well as in the axoplasm. The NPY fibers were closely apposed to smooth muscle cells and pericytes of small blood vessels in the cortex.(ABSTRACT TRUNCATED AT 250 WORDS)
Anat Rec 1986 Mar
PMID:Neuropeptide tyrosine (NPY)-like immunoreactivity in adrenal chromaffin cells and intraadrenal nerve fibers of rats. 351 14

Superoxide anion production in neutrophils plays an important role in the microbicidal defense system in the body. In this study, isolated rat neutrophils were stimulated experimentally and examined by electron microscopy to determine the site of superoxide production and its subsequent translocation during different cell stimulation time periods. Blood and peritoneal neutrophils were incubated for periods of 5, 10, and 15 min with phorbol 12-myristate 13-acetate (PMA), N-formyl-Met-Leu-Phe (fMLP), and combinations of PMA and cytochalasin B (CB) and fMLP and CB. Ultracytochemical detection of O(2)(-) was performed with the 3, 3'-diaminobenzidine-manganese (DAB/Mn) cytochemical method and cationized ferritin (CF) particles were added to stimulation media to monitor endocytotic events that occurred during neutrophil stimulation. Unstimulated neutrophils were devoid of O(2)(-) activity in cytoplasmic granules and at the plasma membrane surface. After 5 min stimulations with PMA, PMA + CB, or fMLP + CB, electron-dense DAB/Mn reaction product was detected in small, centrally located tubular compartments within the neutrophils. CF particles which were added to the stimulation media became internalized in endocytotic vesicles after 5 min stimulation; these vesicles were devoid of O(2)(-) activity. At 10 min stimulation with PMA, O(2)(-)-positive granules subsequently fused with each other and translocated to sub-plasma membrane regions where they either contacted the plasma membrane or fused with CF-containing endocytotic vesicles. Little reaction product was observed on the surface of the neutrophils. Spectrophotometric comparison of the stimulatory effects of PMA, fMLP, and fMLP + CB revealed different rates and yields of O(2)(-) production. Results from this study suggest that the O(2)(-)-producing sites of rat neutrophils originate intracellularly and translocate to the plasma membrane surface following stimulation with PMA, PMA + CB, and fMLP + CB, but not with fMLP or CB alone. Furthermore, these compartments appear to possess the ability to fuse with endocytotic vesicles, a process that may be linked to intracellular microbicidal activity in circulating and tissue neutrophils.
Anat Rec 2000 02 01
PMID:Ultracytochemical study on the localization of superoxide producing sites in stimulated rat neutrophils. 1064 63

Heme catalases are homotetrameric enzymes with a highly conserved complex quaternary structure, and their functional role is still not well understood. Proteus mirabilis catalase (PMC), a heme enzyme belonging to the family of NADPH-binding catalases, was efficiently overexpressed in E. coli. The recombinant catalase (rec PMC) was deficient in heme with one-third heme and two-thirds protoporphyrin IX as determined by mass spectrometry and chemical methods. This ratio was influenced by the expression conditions, but the enzyme-specific activity calculated relative to the heme content remained unchanged. The crystal structure of rec PMC was solved to a resolution of 2.0 A, the highest resolution obtained to date with PMC. The overall structure was quite similar to that of wild-type PMC, and it is surprising that the absence of iron had no effect on the structure of the active site. Met 53 close to the essential His 54 was found less oxidized in rec PMC than in the wild-type enzyme. An acetate anion was modeled in an anionic pocket, away from the heme group but important for the enzymatic reaction. An alternate conformation observed for Arg 99 could play a role in the formation of the H-bond network connecting two symmetrical subunits of the tetramer.
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PMID:High-resolution structure and biochemical properties of a recombinant Proteus mirabilis catalase depleted in iron. 1248 20

The risk of dispersing foot-and-mouth disease virus into the atmosphere, and spreading it to susceptible holdings as a result of burning large numbers of carcases together on open pyres, has been estimated for six selected pyres burned during the 2001 outbreak in the UK. The probability of an animal or holding becoming infected was dependent on the estimated level of exposure to the virus predicted from the concentrations of virus calculated by the Met Office, Bracknell. In general, the probability of infection per animal and per holding decreased as their distance from the pyre increased. In the case of two of the pyres, a holding under the pyre plumes became infected on a date consistent with when the pyre was lit. However, by calculating their estimated probability of infection from the pyres it was concluded that it was unlikely that in either case the pyre was the source of infection.
Vet Rec 2004 Feb 07
PMID:Quantitative estimates of the risk of new outbreaks of foot-and-mouth disease as a result of burning pyres. 1502 72

The subcellular distributions of the opioid growth factor (OGF), [Met(5)]-enkephalin, and opioid growth factor receptor (OGFr) in the epithelium of the rat tongue were determined in order to reveal structure-function relationships. Laser scanning confocal microscopic analysis showed that both OGF and OGFr were colocalized in the paranuclear cytoplasm and in the nuclei of keratinocytes in the stratum basale. Using immunoelectron microscopy and postembedding techniques, double labeling experiments disclosed that complexes of OGF-OGFr were colocalized on the outer nuclear envelope, in the paranuclear cytoplasm, perpendicular to the nuclear envelope in a putative nuclear pore complex, and in the nucleus adjacent to heterochromatin. Anti-OGF IgG alone was detected in the cytoplasm, and anti-OGFr IgG alone was associated with the outer nuclear envelope. Study of chronic treatment with the opioid antagonist, naltrexone (NTX), which blocks opioid-receptor binding, revealed the presence of OGFr immunoreactivity alone in the cytoplasm and the nucleus; some OGF-OGFr complexes were also observed. Colocalization of OGFr and karyopherin (importin) beta was recorded in the cytoplasm and nucleus. These results in tongue epithelium are the first to suggest that OGFr resides on the outer nuclear envelope, where OGF interacts with OGFr; that the OGF-OGFr complex translocates between cytoplasm and nucleus at the nuclear pore; and that the nuclear localization signal of OGFr interacts with karyopherin beta for nuclear transport. These novel data also indicate that signal transduction for cell proliferation appears to involve an OGF-OGFr complex that interfaces with chromatin in the nucleus. Moreover, the unique finding that OGFr was found in the cytoplasm and nucleus in NTX-treated specimens may suggest that NTX-OGFr complexes have the same pathway as OGF-OGFr.
Anat Rec A Discov Mol Cell Evol Biol 2005 Jan
PMID:Nucleocytoplasmic distribution of opioid growth factor and its receptor in tongue epithelium. 1558 33

The aims of this study were to statistically reassess the likelihood that windborne spread of foot-and-mouth disease (FMD) virus (FMDV) occurred at the start of the UK 1967 to 1968 FMD epidemic at Oswestry, Shropshire, and to derive dose-response probability of infection curves for farms exposed to airborne FMDV. To enable this, data on all farms present in 1967 in the parishes near Oswestry were assembled. Cases were infected premises whose date of appearance of first clinical signs was within 14 days of the depopulation of the index farm. Logistic regression was used to evaluate the association between infection status and distance and direction from the index farm. The UK Met Office's NAME atmospheric dispersion model (ADM) was used to generate plumes for each day that FMDV was excreted from the index farm based on actual historical weather records from October 1967. Daily airborne FMDV exposure rates for all farms in the study area were calculated using a geographical information system. Probit analyses were used to calculate dose-response probability of infection curves to FMDV, using relative exposure rates on case and control farms. Both the logistic regression and probit analyses gave strong statistical support to the hypothesis that airborne spread occurred. There was some evidence that incubation period was inversely proportional to the exposure rate.
Vet Rec 2011 Sep 24
PMID:Reanalysis of the start of the UK 1967 to 1968 foot-and-mouth disease epidemic to calculate airborne transmission probabilities. 2184 85

The ability to restart broken DNA replication forks is essential across all domains of life. In Escherichia coli, the priA, priB, priC, and dnaT genes encode the replication restart proteins (RRPs) to accomplish this task. PriA plays a critical role in replication restart such that its absence reveals a dramatic phenotype: poor growth, high basal levels of SOS expression, poorly partitioned nucleoids (Par-), UV sensitivity, and recombination deficiency (Rec-). PriA has 733 amino acids, and its structure is composed of six domains that enable it to bind to DNA replication fork-like structures, remodel the strands of DNA, interact with SSB (single-stranded DNA binding protein), PriB, and DnaT, and display ATPase, helicase, and translocase activities. We have characterized a new priA mutation called priA316::cat It is a composite mutation involving an insertion that truncates the protein within the winged-helix domain (at the 154th codon) and an ACG (Thr)-to-ATG (Met) mutation that allows reinitiation of translation at the 157th codon such that PriA is expressed in two pieces. priA316::cat phenotypes are like those of the wild type for growth, recombination, and UV resistance, revealing only a slightly increased level of SOS expression and defects in nucleoid partitioning in the mutant. Both parts of PriA are required for activity, and the N-terminal fragment can be optimized to yield wild-type activity. A deletion of the lon protease suppresses priA316::cat phenotypes. We hypothesize the two parts of PriA form a complex that supplies most of the PriA activity needed in the cell.IMPORTANCE PriA is a highly conserved multifunctional protein that plays a crucial role in the essential process of replication restart. Here we characterize an insertion mutation of priA with an intragenic suppressor such that it is now made in two parts. These two pieces split the winged-helix domain to separate the N-terminal 3' DNA-binding domain from the C-terminal domain of PriA. It is hypothesized that the two pieces form a complex that is capable of almost wild type priA function. The composite mutation leads to a moderate level of SOS expression and defects in partitioning of the chromosomes. Full function is restored by deletion of lon, suggesting that stability of this complex may be a reason for the partial phenotypes seen.
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PMID:A priA Mutant Expressed in Two Pieces Has Almost Full Activity in Escherichia coli K-12. 2860 60