A sequence motif that is conserved in a number of S-adenosylmethionine (SAM)-utilizing methyltransferases and is implicated in SAM binding was identified in the N-terminal portion of NS5 proteins of flaviviruses and in lambda 2 protein of reovirus. An additional conserved motif was shared by these viral proteins and two distinct groups of methyltransferases including as the prototypes Rhodobact...

Glycine N-methyltransferase (EC 2.1.1.20) was recently identified as a major folate binding protein of rat liver cytosol (Wagner, C., and Cook, R. J. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 3631-3634). Activity of the enzyme is inhibited when the natural folate ligand, 5-methyltetrahydropteroylpentaglutamate (5-CH3-H4PteGlu5), is bound. It has been suggested that glycine N-methyltransferase pl...

Fifteen years ago epinephrine cells were shown to be present in the medulla oblongata of the rat. These cell groups (C1 and C2) were thought to supply the epinephrine innervation in the rest of the central nervous system. In this study I demonstrate the presence of epinephrine-producing neurons in the forebrain of the young rat. Neurons that are immunopositive for phenylethanolamine N-methyltra...

Hepatitis E virus (HEV) is a major cause of hepatitis in normal and organ transplant individuals. HEV open reading frame-1 encodes a polypeptide comprising of the viral nonstructural proteins as well as domains of unknown function such as the macro domain (X-domain), V, DUF3729 and Y. The macro domain proteins are ubiquitously present from prokaryotes to human and in many positive-strand RNA vi...

The rescue of lymphocytes from methotrexate (MTX) growth inhibition by 5-methyltetrahydrofolate (5-methyl-THF) and 5-formyltetrahydrofolate (5-formyl-THF) has been studied. Rescue by 5-methyl-THF is selective for cells with high levels of homocysteine:5-methyl-THF methyl-transferase (methyltransferase). At MTX concentrations which inhibited growth greater than or equal to 85% in both leukemic T...

Addition of isoproterenol to isolated rat adipocytes prelabeled with [32P]phosphate caused an increase in the phosphorylation and activation of phospholipid methyltransferase. 32P-Labeled phospholipid methyltransferase was recovered by immunoprecipitation and gel electrophoresis. Analysis of 32P-labeled peptides revealed one site of phosphorylation regulated by isoproterenol, and analysis of ph...

The loss of expression of the enzyme O6-methylguanine-DNA methyltransferase (the Mex- phenotype), which often results from cellular transformation, confers hypersensitivity to alkylating agents. We have observed two unrelated examples in which human cell lines have undergone a spontaneous alteration in their Mex phenotype during propagation in vitro. The change was reversible and was not the re...

Selectivity of catechol O-methyltransferase has been examined for the three ring-fluorinated norepinephrines to elucidate the role of acidity of the phenolic groups in their methylation. Substitution of fluorine at the 5-position of norepinephrine reverses the selectivity of catechol O-methyltransferase so that p-O-methylation predominates. The 5-fluoro substituent also causes the pKa of the p-...

We have isolated a multiple-aminoglycoside-resistant Escherichia coli strain, strain ARS3, and have been the first to identify a novel plasmid-mediated 16S rRNA methyltransferase, NpmA. This new enzyme shared a relatively low level of identity (30%) to the chromosomally encoded 16S rRNA methyltransferase (KamA) of Streptomyces tenjimariensis, an actinomycete aminoglycoside producer. The introdu...