Plasmid DNA (pUC19 and pBR322) was sequence-specifically, covalently labelled with Cy3 fluorophores using a newly synthesised N-adenosylaziridine cofactor and the DNA methyltransferase M.TaqI. The fluorescently labelled plasmids were used for transfection of mammalian cells and their intracellular distribution was visualised by epifluorescence and confocal fluorescence microscopy. Although these prokaryotic plasmids do not contain nuclear import sequences, translocation into the nuclei was observed. (C) 2007 Elsevier Ltd. All rights reserved.
Synthesis of S-Adenosyl-L-homocysteine Capture Compounds for Selective Photoinduced Isolation of Methyltransferases
Fisherman's friends: Molecular fishing hooks were developed to selectively tag and isolate methyltransferases. These capturecompounds contain the cofactor product S‐adenosyl‐L‐homocysteine for directed, noncovalent prebinding to the enzymes (1), a photoreactive group for covalent crosslinking (2) and biotin for isolation with streptavidin‐coated magnetic beads (3).