Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A general method was developed for the isolation of Salmonella typhimurium LT2 Mu d1-8 (Aprlac) operon fusions in a gene displacing a Tn10 insertion. Random Mu d1-8 fusion pools were prepared to grow phage P22 lysates which transduced chlC::Tn10 to AprTets on fusaric acid-ampicillin plates. Among these AprTets potential chlC::Mu d1-8 fusions, a simple spot test identified the fusions that were closely linked to the Tn10 insertion in chlC. Out of 68 AprTets isolates 7 chlC::Mu d1-8 fusions with a nitrate-induced Lac+ phenotype were obtained. When oxrA::Tn10 was transduced into these chlC::Mu d1-8 fusions, they became Lac- even in the presence of nitrate, confirming that they were chlC::Mu d1-8 fusions.
Mol Gen Genet 1986 Nov
PMID:A general method for isolation of Mu d1-8(Aprlac) operon fusions in Salmonella typhimurium LT2 from Tn10 insertion strains: chlC::Mu d1-8. 302 1

Seven genomic libraries of chromosomal Escherichia coli K12 wild-type DNA were constructed in plasmid vectors. These were used to transform chl insertion mutants. Selection for growth on nitrate under anaerobic conditions yielded four plasmids which complemented mutants of the chlA, B, E and G types. The chromosomal fragments were mapped with restriction enzymes and subcloned. Three complementation groups were observed among the chlA mutants and two among the chlE mutants. The established complementation groups plus mutants of the chlD type represent eight distinct functions, which are all believed to be required for the molybdenum cofactor activity in the reduction of nitrate to nitrite by E. coli.
Mol Gen Genet 1987 Feb
PMID:Cloning of seven differently complementing DNA fragments with chl functions from Escherichia coli K12. 303 39

Nitrate reductase is demonstrated to exert an autogenous control on its own synthesis. This effect requires the participation of the molybdenum cofactor. Use of strains in which the control region of the nar operon is mutated reveals two loci in this region: one, affected in strain LCB94, is common to both autoregulation and induction by nitrate while the other, mutated in strain LCB188, is specific for the induction by nitrate. It is proposed that the autogenous control prevents the unnecessary accumulation of the nitrate reductase subunits in the cytoplasm.
Mol Gen Genet 1986 Jul
PMID:Autoregulation of the nar operon encoding nitrate reductase in Escherichia coli. 309 94

Two classes of mutants defective in benzyl viologen-linked formate dehydrogenase (FDH-BV) activity were isolated from Escherichia coli K12. Class I consisted of four mutants which were specifically devoid of FDH-BV activity. Their mutation mapped between the ssb and melA genes at 92 min on the genome, at a site recently designated fdhF by Pecher et al. (1985). The direction of transcription of gene fdhF was found to be counterclockwise on the E. coli chromosome in one Mudl(Aprlac) fusion mutant. Expression of the lac operon in this mutant was induced by formate and repressed by nitrate, nitrite or trimethylamine N-oxide. It was found to be dependent on the positive control exerted by the fdhA, B and C genes, possibly involved in selenium incorporation, and by an hydB gene affecting the formate hydrogenlyase pathway. Class II, represented by one Mudl(Aprlac) mutant, exhibited no FDH-BV activity and a reduced level of hydrogenase activity. The relevant fdv mutation was shown to be located at 58 min and to affect the expression of fdhF.
Mol Gen Genet 1987 Aug
PMID:Regulation of the fdhF gene encoding the selenopolypeptide for benzyl viologen-linked formate dehydrogenase in Escherichia coli. 311 41

The main nitrogen source for most higher plants is soil nitrate. Prior to its incorporation into amino acids, plants reduce nitrate to ammonia in two enzymatic steps. Nitrate is reduced by nitrate reductase to nitrite, which is further reduced to ammonia by nitrite reductase. In this paper, the complete primary sequence of the precursor protein for spinach nitrite reductase has been deduced from cloned cDNAs. The cDNA clones were isolated from a nitrate-induced cDNA library in two ways: through the use of oligonucleotide probes based on partial amino acid sequences of nitrite reductase and through the use of antibodies raised against purified nitrite reductase. The precursor protein for nitrite reductase is 594 amino acids long and has a 32 amino acid extension at the N-terminal end of the mature protein. These 32 amino acids most likely serve as a transit peptide involved in directing this nuclear-encoded protein into the chloroplast. The cDNA hybridizes to a 2.3 kb RNA whose steady-state level is markedly increased upon induction with nitrate.
Mol Gen Genet 1988 Apr
PMID:Isolation of cDNA clones coding for spinach nitrite reductase: complete sequence and nitrate induction. 316 66

The stimulatory effects of two thiol (SH) group oxidants, methylmethane thiosulfonate (MMTS) and diazene dicarboxylic acid bis [N,N-dimethylamide] (diamide), on the kinetics of ouabain-resistant (OR) K:Cl [co]-transport in low K (LK) sheep red blood cells were compared with the effects of alkylating agents, notably N-ethylmaleimide (NEM). At low concentrations, both MMTS and diamide stimulated K:Cl [co]-transport, and with a latency period, as measured by OR zero-trans K efflux and OR uptake of external Rb, Rbo, as K congener in Cl and NO3 media. At high concentrations the effect of diamide saturated, and that of MMTS disappeared. The stimulatory effect of MMTS was partially reversed by the reducing agent dithiothreitol (DTT) known to fully restore the diamide-activated K flux (Lauf, J. Memb. Biol. 101:179-188, 1988). In diamide preequilibrated LK sheep red cells, the Km of K:Cl [co]-transport for external Cl, Clo, was 84.3 mM, and 18.7 mM for Rbo, with nearly identical Vmax values around 4 mmol Rb/L cells x h for K (Rb) fluxes in Cl and after correction for the small Cl-independent component. Zero net K (Rb) flux existed at Kc (cell K)/Rbo concentration ratios, [K]c/[Rb]c, of 0.8 i.e. when the electrochemical driving forces across the membrane were about equal. The measured K efflux/Rb influx ratios were almost twice those predicted from [K]c/[Rb]o and the Cl equilibrium potential suggesting that the diamide-stimulated K (Rb) flux may occur through non-diffusional, carrier-mediated transport.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Biochem
PMID:Kinetic comparison of ouabain-resistant K:Cl fluxes (K:Cl [Co]-transport) stimulated in sheep erythrocytes by membrane thiol oxidation and alkylation. 318 22

A nar-lac operon fusion was used to isolate a mutant in which the expression of the nar operon was no longer repressed by oxygen. The nard mutation, located upstream of the nar structural genes, was found to be cis dominant; it led to independence from the Fnr protein which, in the wild-type strain, exerts a strict positive control on the nar operon. Both other known controls, nitrate induction and autoregulation, were unaffected. It is proposed that molecular oxygen controls the expression of nar via Fnr and that the nard mutation affects the Fnr binding site of the narGHI control region.
Mol Gen Genet 1986 Nov
PMID:Alteration by mutation of the control by oxygen of the nar operon in Escherichia coli. 354 21

The X-ray structure of the nucleosome core particle was solved at 7 A resolution using the method of multiple isomorphous replacement based on two isomorphous derivatives, each containing a different multiple heavy-atom compound. The preparation of these heavy-atom compounds and their application to this macromolecular structure determination are described. The first of these reagents, TAMM (tetrakis(acetoxymercuri)methane), was solubilized by the addition of an excess of glycylglycine and, when added to crystals of the nucleosome core particle, produced a derivative with a single major site. Despite the large mass of 206,000 daltons per asymmetric unit, the position of the TAMM molecule was found in these crystals using the difference Patterson technique. This compound was sufficiently electron-dense to produce a unique solution, whereas the mono-mercurial, methylmercury nitrate had been inadequate. The second reagent, PIP (di-mu-iodobis(ethylenediamine)diplatinum(II) nitrate), is freely soluble in aqueous solution and, on addition to the crystals, labelled the histone proteins at several sites. The locations of the PIP groups were determined from difference Fourier and Patterson maps. The X-ray structure and solution characterization of this compound are reported. These multiple heavy-atom compounds appear to be generally applicable to X-ray structure determination, and are particularly useful in conjunction with crystals having asymmetric units of large volume but lacking non-crystallographic symmetry elements.
J Mol Biol 1987 Apr 20
PMID:Multiple heavy-atom reagents for macromolecular X-ray structure determination. Application to the nucleosome core particle. 365 3

The rate of loss of the sulfhydryl group, determined with the Ellman reagent, was used to derive second order rate constants for the reaction of a series of organic nitrates with a series of sulfhydryl compounds. For the organic nitrates, increases in the rate of reaction with cysteine, in general, ran parallel both with increases in pharmacological potency (flow in the Langendorff heart) and with increases in total clearance. Cysteine was the most active sulfhydryl compound examined, which is compatible with a possible role as an important nitrate receptor. Under some conditions the rate of loss of the sulfhydryl group was much greater than the rate of formation of nitrite ion. This indicates the presence of a reaction intermediate, probably a thionitrate. It is suggested that, in vivo, a thionitrate could function as an important intermediate in the activation of guanylate cyclase.
Mol Pharmacol 1985 Dec
PMID:The reaction between organic nitrates and sulfhydryl compounds. A possible model system for the activation of organic nitrates. 407 11

Some of the properties of the RNA polymerase purified from SPO1-infected Bacillus subtilis have been compared with the properties of RNA polymerase from uninfected cells (core + sigma). The two enzymes synthetize RNA from nonoverlapping regions on SPO1 DNA, and they lead to the retention of different restriction fragments of SPO1 DNA on cellulose-nitrate filters. The action of the positively regulating product of gene 28 of SPO1 (gp 28) has been analyzed. The isolated gp 28 has been shown to be unable to increase the dissociation rate of core + sigma from SPP1 DNA, while it efficiently blocks the initiation of RNA synthesis if it is added to performed complexes between core + sigma and SPP1 DNA in 0.2 M NaCl.
Mol Gen Genet 1981
PMID:Effects of the positively regulating product of gene 28 of the B. subtilis phage SPO1 on in vitro transcription. 617 44


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