Kinetics of Methylation by EcoP1I DNA Methyltransferase.

EcoP1I DNA MTase (M.EcoP1I), an N(6)-adenine MTase from bacteriophage P1, is a part of the EcoP1I restriction-modification (R-M) system which belongs to the Type III R-M system. It recognizes the sequence 5'-AGACC-3' and methylates the internal adenine.

Multiple conserved domains of the nucleoporin Nup124p and its orthologs Nup1p and Nup153 are critical for nuclear import and activity of the fission yeast Tf1 retrotransposon.

The nucleoporin Nup124p is a host protein required for the nuclear import of both, retrotransposon Tf1-Gag as well as the retroviral HIV-1 Vpr in fission yeast. The human nucleoporin Nup153 and the Saccharomyces cerevisiae Nup1p were identified as orthologs of Nup124p. In this study, we show that all three nucleoporins share a large FG/FXFG-repeat domain and a C-terminal peptide sequence, GRKIxxxxxRRKx, that are absolutely essential for Tf1 retrotransposition.

S-Adenosyl-L-methionine-dependent restriction enzymes.

Restriction-modification (R-M) enzymes are classified into type I, II, III, and IV, based on their recognition sequence, subunit composition, cleavage position, and cofactor requirements. While the role of S-Adenosyl-L-methionine (AdoMet) as the methyl group donor in the methylation reaction is undisputed, its requirement in DNA cleavage reaction has been subject to intense study. AdoMet is a prerequisite for the DNA cleavage by most type I enzymes known so far, with the exception of R.

Single-stranded DNA binding and methylation by EcoP1I DNA methyltransferase.

EcoP1I methyltransferase (M.EcoP1I) belongs to the type III restriction-modification system encoded by prophage P1 that infects Escherichia coli. Binding of M.