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)

The method of isolation and partial purification of DNA-cytosine-methyltransferase (DC-methylase) from E. coli C is described. The enzyme underwent approximately 100-fold purification. The obtained preparation of DC-methylase can be additionally considerably purified by sedimentation in sucrose gradient. Native molecular weight of DC-methylase from E. coli C. is 70,000. The activity of enzyme does not depend on the Mg2+ ions. DC-methylase E. coli C provides DNA of lambda phage in vitro with full resistance against restriction endonuclease EcoRII. In DNA methylated by DC-methylase the modified cytosine, mainly in C-MC and C-MC-T sequences, corresponds to the pyrimidine sequences of specific site EcoRII. DNA of lambda.B phage contains approximately 80 sites for modification by DC-methylase E. coli C. The results obtained point to the same specificity in vitro of DNA-cytosine-methylase E. coli C and DNA-methylase EcoRII.
Mol Biol (Mosk)
PMID:[Isolation and properties of DNA-cytosine methyltransferase from Escherichia coli C]. 37 62

Specific radioactive enzyme assays were developed to measure the effect of growth hormone on kidney transamidinase and liver methyltransferase in the hypophysectomized rat. In contrast to minimal changes (20%) in liver methyltransferase, kidney transamidinase was decreased threefold in the hypophysectomized rat. Enzyme activities were equal to normal values in those rats receiving growth hormone for three days. The formation of creatine from radioactive precursors and the uptake of 14C-creatine in muscle was examined under these conditions. After injection of 14C-arginine in the hypophysectomized rat, the 14C-creatine content of muscle was greatly decreased compared to sham operated controls and the 14C-creatine content was normal after growth hormone administration. After injection of 14C-guanidoacetate and of 14-creatine, the 14C-creatine content of muscle was decreased in the hypophysectomized rat, but was equal to sham control values in rats receiving growth hormone. These studies indicate that the uptake of newly synthesized creatine by muscle is impaired in the hypophysectomized rat and that growth hormone can have a role in controlling the rate of creatine uptake by muscle in addition to its effect on kidney transamidinase and to other factors involved in creatine metabolism.
Mol Cell Biochem 1979 May 21
PMID:Growth hormone effects on creatine uptake by muscle in the hypophysectomized rat. 46 Jan 77

A comparative study of the position specificity of tRNA-methylases from normal and tumour tissues was performed on yeast tRNA1Val as the substrates using partially purified enzyme preparations from rat kidney and carcinoma RA. As in the case of rat liver and Novikoff hepatoma, two methylated compounds are formed in yeast tRNA1Val under the action of rat kidney and carcinoma enzyme preparations: m5C is formed in the sequence C49--C52 located in the extra loop and A59 in the Tpsi-loop is is converted into m1A. The activity of m5C-methylase [S-Ado-Met-tRNA-(cytosine-5)methyltransferase] (E. C. 2.1.1.29) is approximately equal in both tissues, whereas the activity of m1A-methylase [S-Ado-Met-tRNA-(adenine-1)methyltransferase] (E. C. 2.1.1.36) in carcinoma is twice as high as in the kidney. The two enzymes do not differ in their position specificity.
Mol Biol (Mosk)
PMID:[Comparative study of the tRNA-methylases of normal and tumor tissues. II. Positional specificity of renal and carcinoma RA methylases]. 61 46

Rat liver nuclear 30 S ribonucleoprotein particles containing pre-mRNA and nuclear sap proteins have been shown to modify in vitro the synthetic dinucleotide ppGpC in the presence of GTP and S-adenosyl-L-methionine (SAM) by the formation of a blocked and methylated (capped) structure 7(meG(5')ppp(5'-GmepC. In the absence of SAM the predominant reaction was GpppGpC. Our results indicate that the 30S ribonucleoprotein particles (informofers) as well as the proteins of the nuclear sap possess both guanylyltransferase, N7-, and 2-o-methyltransferase activities.
Mol Biol Rep 1978 Jun 16
PMID:Methylated cap formation by enzymes bound to nuclear informofer particles. 68 86

Two different lincomycin-resistance determinants (lmrA and lmrB) from Streptomyces lincolnensis 78-11 were cloned in Streptomyces lividans 66 TK23. The gene lmrA was localized on a 2.16 kb fragment, the determined nucleotide sequence of which encoded a single open reading frame 1446 bp long. Analysis of the deduced amino acid sequence suggested the presence of 12 membrane-spanning domains and showed significant similarities to the methylenomycin-resistance protein (Mmr) from Streptomyces coelicolor, the QacA protein from Staphylococcus aureus, and several tetracycline-resistance proteins from both Gram-positive and Gram-negative bacteria, as well as to some sugar-transport proteins from Escherichia coli. The lmrB gene was actively expressed from a 2.7 kb fragment. An open reading frame of 837 bp could be localized which encoded a protein that was significantly similar to 23S rRNA adenine(2058)-N-methyltransferases conferring macrolide-lincosamide-streptogramin resistance. LmrB also had putative rRNA methyltransferase activity since lincomycin resistance of ribosomes was induced in lmrB-containing strains. Surprisingly, both enzymes, LmrA and LmrB, had a substrate specificity restricted to lincomycin and did not cause resistance to other lincosamides such as celesticetin and clindamycin, or to macrolides.
Mol Microbiol 1992 Aug
PMID:Molecular cloning and characterization of two lincomycin-resistance genes, lmrA and lmrB, from Streptomyces lincolnensis 78-11. 132 13

Infective (nodulating) Rhizobium leguminosarum biovar viciae (R.l. viciae) bacteria release Nod factors which stimulate the release of nodulation gene-inducing flavanones and chalcones from roots of the host plant Vicia sativa subsp. nigra (K. Recourt et al., Plant Mol Biol 16: 841-852; H.P. Spaink et al., Nature 354: 125-130). The hypothesis that this release results from increased synthesis of flavonoids was tested by studying the effect of inoculation of V. sativa with infective and uninfective R.l. viciae bacteria on (i) activity of L-phenylalanine ammonia-lyase, (ii) level of chalcone synthase mRNA, and (iii) activity of (eriodictyol) methyltransferase in roots. Consistent with the hypothesis, each of these parameters was found to increase 1.5 to 2-fold upon inoculation with infective R.l. viciae bacteria relative to the situation for uninoculated roots and for roots inoculated with uninfective rhizobia.
Plant Mol Biol 1992 Jun
PMID:Activation of flavonoid biosynthesis in roots of Vicia sativa subsp. nigra plants by inoculation with Rhizobium leguminosarum biovar viciae. 137 64

The TRM1 gene of Saccharomyces cerevisiae codes for a tRNA modification enzyme, N2,N2-dimethylguanosine-specific tRNA methyltransferase (m2(2)Gtase), shared by mitochondria and nuclei. Immunofluorescent staining at the nuclear periphery demonstrates that m2(2)Gtase localizes at or near the nuclear membrane. In determining sequences necessary for targeting the enzyme to nuclei and mitochondria, we found that information required to deliver the enzyme to the nucleus is not sufficient for its correct subnuclear localization. We also determined that mislocalizing the enzyme from the nucleus to the cytoplasm does not destroy its biological function. This change in location was caused by altering a sequence similar to other known nuclear targeting signals (KKSKKKRC), suggesting that shared enzymes are likely to use the same import pathway as proteins that localize only to the nucleus. As with other well-characterized mitochondrial proteins, the mitochondrial import of the shared methyltransferase depends on amino-terminal amino acids, and removal of the first 48 amino acids prevents its import into mitochondria. While this truncated protein is still imported into nuclei, the immunofluorescent staining is uniform throughout rather than at the nuclear periphery, a staining pattern identical to that described for a fusion protein consisting of the first 213 amino acids of m2(2)Gtase in frame with beta-galactosidase. As both of these proteins together contain the entire m2(2)Gtase coding region, the information necessary for association with the nuclear periphery must be more complex than the short linear sequence necessary for nuclear localization.
Mol Cell Biol 1992 Dec
PMID:Separate information required for nuclear and subnuclear localization: additional complexity in localizing an enzyme shared by mitochondria and nuclei. 144 94

Many DNA sequences have been studied by X-ray crystallography with the goal of deciphering a sequence-structure code. We have determined the helical repeats of two B-type DNA decamers in solution employing an electrophoretic method based on phasing of bent segments. The decamers contain recognition sites for the dcm methyltransferase and for the restriction nuclease NarI with a mutational hotspot. Their helical repeats are 10.59(+/- 0.05) bp and 10.52(+/- 0.03) bp, respectively, whereas crystallographic analysis yielded 10.0 bp in the solid state. This difference is greater than that for the transition between B- and A-type DNA in solution. Thus, reliable information about the polymorphism of DNA in solution must be based on both X-ray and solution data. We describe a generally applicable approach to accurately determine helical repeats of small DNA duplexes in solution.
J Mol Biol 1992 Nov 20
PMID:An accurate method for determining the helical repeat of DNA in solution reveals differences to the crystal structures of two B-DNA decamers. 145 42

The isolation and characterization of cDNA and homologous genomic clones encoding the lignin O-methyltransferase (OMT) from maize is reported. The cDNA clone has been isolated by differential screening of maize root cDNA library. Southern analysis indicates that a single gene codes for this protein. The genomic sequence contains a single 916 bp intron. The deduced protein sequence from DNA shares significant homology with the recently reported lignin-bispecific caffeic acid/5-hydroxyferulic OMTs from alfalfa and aspen. It also shares homology with OMTs from bovine pineal glands and a purple non-sulfur photosynthetic bacterium. The mRNA of this gene is present at different levels in distinct organs of the plant with the highest accumulation detected in the elongation zone of roots. Bacterial extracts from clones containing the maize OMT cDNA show an activity in methylation of caffeic acid to ferulic acid comparable to that existing in the plant extracts. These results indicate that the described gene encodes the caffeic acid 3-O-methyltransferase (COMT) involved in the lignin bio-synthesis of maize.
Plant Mol Biol 1992 Dec
PMID:Structure and expression of the lignin O-methyltransferase gene from Zea mays L. 146 25

Chemical probing of the structures of a few very similar 30 base-pair duplexes containing a 6-O-methylguanine (meG) residue at the 16th position reveals that the modified base simultaneously perturbs the helical structure in two ways; it preferentially unstacks the 3' neighbouring base residue (thymine in this study) on the same strand and it unstacks the pyrimidine to which it is base-paired. Depending on its neighbouring 5' base residue and the base-pairing pyrimidine, this perturbation can extend to a few base-pairs in both 3' and 5' directions from the abnormal base-pair. These perturbations can be detected by cleavage at the site for the restriction enzyme MaeII. The unstaking of the C in the meG.C and A.C base-pairs may explain the de novo methylation of these helices by the human DNA-(cytosine-5-)methyltransferase. Interestingly, the kinetics of repair of the 6-O-methylguanine-containing dinucleotides by the cloned human methylguanine methyltransferase appears to be largely determined by the strength of the stacking interaction between the 6-O-methylguanine and the 5' neighbouring base.
J Mol Biol 1992 Dec 20
PMID:Structure-related properties of the mutagenic lesion 6-O-methylguanine in DNA. 147 83


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