Formation of m2G6 in Methanocaldococcus jannaschii tRNA catalyzed by the novel methyltransferase Trm14

The modified nucleosides N2-methylguanosine and N22-dimethylguanosine in transfer RNA occur at five positions in the D and anticodon arms, and at positions G6 and G7 in the acceptor stem. Trm1 and Trm11 enzymes are known to be responsible for several of the D/anticodon arm modifications, but methylases catalyzing post-transcriptional m2G synthesis in the acceptor stem are uncharacterized. Here, we report that the MJ0438 gene from Methanocaldococcus jannaschii encodes a novel S-adenosylmethionine-dependent methyltransferase, now identified as Trm14, which generates m2G at position 6 in tRNACys. The 381 amino acid Trm14 protein possesses a canonical RNA recognition THUMP domain at the amino terminus, followed by a γ-class Rossmann fold amino-methyltransferase catalytic domain featuring the signature NPPY active site motif. Trm14 is associated with cluster of orthologous groups (COG) 0116, and most closely resembles the m2G10 tRNA methylase Trm11. Phylogenetic analysis reveals a canonical archaeal/bacterial evolutionary separation with 20–30% sequence identities between the two branches, but it is likely that the detailed functions of COG 0116 enzymes differ between the archaeal and bacterial domains. In the archaeal branch, the protein is found exclusively in thermophiles. More distantly related Trm14 homologs were also identified in eukaryotes known to possess the m2G6 tRNA modification

Zinc alloys coatings applied by the electrolytic method

Przedstawiono wyniki badań powłok stopowych cynku otrzymanych z kąpieli galwanicznych Chemoalloy Fe i Ni CHS. Badano wpływ warunków prądowych współosadzania na morfologię powierzchni powłok. Stwierdzono, że z kąpieli Zn-Fe otrzymuje się błyszczące powłoki stopowe. Wzrost temperatury kąpieli Zn-Fe do 25°C spowodował zmniejszenie grubości powłok oraz zmatowienie powierzchni. Otrzymane powłoki stopowe Zn-Ni charakteryzowały się dużą równomiernością i brakiem połysku. Wraz ze wzrostem gęstości prądu powstały powłoki o płytkowej strukturze.Study results dealing with zinc alloy coatings obtained from electroplating baths Chemoalloy Fe and Ni CHS are presented in the paper. An effect of current codeposition on the morphology of surface coatings was tested. It was found that a Zn-Fe dip gave the shiny alloy coatings. A temperature increase to 25 °C of Zn-Fe bath caused a reduction of coating thickness and surface dulling. The resulting Zn-Ni alloy coatings were characterized by high uniformity and lack of luster. The coatings of lamellar structure were formed with the increase of electric current density

Studies towards neoglycoconjugates from the monosaccharide determinant of Vibrio cholerae O:1, serotype Ogawa using the diethyl squarate reagent: Carbohyd.Res.

NRC publication: Ye

Encapsulation of fluorescein into nanozeolites L and Y

International audienc

Synthesis of fluorescein by a ship-in-a-bottle method in different zeolites

International audienc