Search results for "nucleotides"
showing 10 items of 297 documents
Production of biologically active light chain of tetanus toxin inEscherichia coli
1993
AbstractThe activity of the light (L) chain of tetanus toxin, and of mutants constructed by site-directed mutagenesis, was studied by expression and purification of the proteins from E. coli. Wild-type recombinant L chain (pTet87) was active in the inhibition of exocytosis from cultured bovine adrenal chromaffin cells, although at a level 5–15% of that of L chain purified from tetanus toxin. L chain mutants which terminated at Leu-438 (pTet89), or which contained a Cys-to-Ser mutation at residue 439 (pTet88) were equally as active as the full-length recombinant protein. The reduced activity of pTet87 L chain correlated with C-terminal proteolysis of the protein upon purification. A tryptic …
Cloning of a novel putative G-protein-coupled receptor (NLR) which is expressed in neuronal and lymphatic tissue.
1993
AbstractA novel G-protein-coupled receptor was isolated from mouse and rat neuronal and lymphatic tissues. The amino acid sequence of the rat receptor (rNLR) shows an overall homology of 80% to a recently cloned receptor from Burkitt's lymphoma cells (BLR1) which is exclusively expressed in lymphatic tissues [(1992) Eur. J. Immunol. 22, 2795]. Much less homology between rNLR and BLR1 was observed at the N-terminus (about 40%), whereas rNLR and the mouse homologue mNLR show 92% amino acid identity. Northern blot analysis of NLR revealed a predominant 5.5 kb mRNA species in various brain regions and neuronal cell lines, whereas in the spleen a 3 kb transcript is predominant. This distribution…
The (2'-5')Oligoadenylate Synthetase is Present in the Lowest Multicellular Organisms, the Marine Sponges. Demonstration of the Existence and Identif…
1995
We have proved the presence of (2'-5')oligoadenylates [(2'-5')An] and oligoadenylate synthetase [(2'-5')An synthetase] in the marine sponge Geodia cydonium. (2'-5')An isolated from sponge crude extract competed with authentic (2'-5')An for binding to polyclonal antiserum against (2'-5')An. HPLC analysis revealed the presence of nucleotides eluting with molecular markers for (2'-5')A oligomers. The biological activity of sponge (2'-5')An was demonstrated by inhibiting the protein biosynthesis in rabbit reticulocyte lysate. The activity of the (2'-5')An synthetase, present in crude sponge extract, was found to be high compared to that in mammalian interferon-treated cell extract. The (2'-5')A…
Determination of total ribonucleotide pool in plant materials by high-pH anion-exchange high-performance liquid chromatography following extraction w…
2005
A new, improved method that only requires a potassium hydroxide extraction procedure is presented for the analysis of a full nucleotide pool in plant materials. Quantification was performed by high-pH anion-exchange chromatography (HPAEC) with UV detection after a potassium hydroxide extraction, and allowed the quantification of 13 linear ribonucleotides in a single run. The method has been validated by comparison of six extraction methods and also by measurement of the intracellular nucleotide levels of three plant species (cell cultures and leaves). The evolution of the nucleotide pool of Nicotiana tabacum cell culture during growth has also been measured, and showed an increase in the po…
HAT1 and HAT2 Proteins Are Components of a Yeast Nuclear Histone Acetyltransferase Enzyme Specific for Free Histone H4
1998
We have analyzed the histone acetyltransferase enzymes obtained from a series of yeast hat1, hat2, and gcn5 single mutants and hat1,hat2 and hat1,gcn5 double mutants. Extracts prepared from both hat1 and hat2 mutant strains specifically lack the following two histone acetyltransferase activities: the well known cytoplasmic type B enzyme and a free histone H4-specific histone acetyltransferase located in the nucleus. The catalytic subunits of both cytoplasmic and nuclear enzymes have identical molecular masses (42 kDa), the same as that of HAT1. However, the cytoplasmic complex has a molecular mass (150 kDa) greater than that of the nuclear complex (110 kDa). The possible functions of HAT1 a…
Energetic aspects of intramolecular coupling between the nucleotide binding site and the distal switch II region of the yeast RAS2 protein
1994
AbstractWe have studied the interaction of the yeast RAS2 protein with guanine nucleotides using energetic parameters for the dissociation of RAS·nucleotide complexes. The results indicated that a Gly → Ser substitution at position 82 led to an altered interaction with GppNHp and, to a lesser extent, also with GDP. It was also possible to conclude that structural perturbation of Gly82 can stimulate nucleotide release by decreasing the energetic barrier for nucleotide dissociation. This, together with the observation that residues 80 and 81 are involved in the response of RAS to nucleotide exchange factors without affecting GDP binding per se, suggests a potential mechanism for exchange fact…
Induction capacity and influence of dThdMP on thymidine kinase activity of type 1 and 2 strains of herpes simplex virus
1978
The thymidine kinase inducing ability of 104 strains of herpes simplex virus was studied comparatively. A pronounced relationship was established between induction of the enzyme and the serotype of the strains. As a rule, the strains of serotype 2 are weaker inducer of dThd- and dCyd-kinase activity than serotype 1 strains. A certain parallelism exists between induction of both enzymes, however the activity of the thymidine kinase increases after infection with herpes simplex virus 4--5 times more than that of the dCyd-kinase. Adaptation of the strains to cell cultures only slightly modifies the inducing ability of the herpes simplex virus strains. The thymidine kinase activity induced by H…
Ribonuclease H levels in herpes simplex virus-infected cells.
1980
Two forms of ribonuclease H (RNase H) have been identified both in uninfected and Herpes Simplex virus (HSV-)infected BHK cells. Identical RNase H species were detected in control- as well as in infected cells. RNase H I and II have not been found to be associated both with host cell DNA polymerase alpha and beta and HSV-induced DNA polymerase. Infection of BHK cells with HSV type 1 does not lead to a pronounced alteration of RNase H II activity but to an increase (3-fold) of the extractable RNase H I activity. RNase H I activity increases to a maximum between 8-10 hours p.i.; the bulk of HSV-DNA synthesis occurs between 6-8 hours p.i. From these experiments we draw the preliminary conclusi…
Polynucleotide differentiation using hybrid solid-state nanopore functionalizing with α-hemolysin
2019
We report results from full atomistic molecular dynamics simulations on the properties of biomimetic nanopores. This latter result was obtained through the direct insertion of an α-hemolysin protein inside a hydrophobic solid-state nanopore. Upon translocation of different DNA strands, we demonstrate here that the theoretical system presents the same discrimination properties as the experimental one obtained previously. This opens an interesting way to promote the stability of a specific protein inside a solid nanopore to develop further biomimetic applications for DNA or protein sequencing.
Synthesis and Characterization of Adducts Derived from the syn-Diastereomer of Benzo[a]pyrene 7,8-Dihydrodiol 9,10-Epoxide and the 5‘-d(CCTATAGATATCC…
1996
5'-d(CCTATAGATATCC) was reacted with each syn-enantiomer of trans-7,8-dihydroxy 9,10-epoxy 7,8,9,10-tetrahydrobenzo[a]pyrene (syn-BPDE). The (-)-enantiomer yielded one dominating adduct, whereas the (+)-enantiomer resulted in two major adducts. As indicated by optical spectroscopic methods, the major adduct derived from both (-)- and (+)-syn-BPDE involves cis addition of the C-10 position of the diol epoxide to the exocyclic amino group of deoxyguanosine [(-)-syn-BPDEc-N2-dG and (+)-syn-BPDEc-N2-dG, respectively], whereas the minor (+)-syn-BPDE adduct is identical to a trans adduct [(+)-syn-BPDEt-N2-dG]. The cis adducts as well as the (+)-syn-BPDEt-N2-dG adduct are chemically stable for sev…