Fig 3.

Inhibition of the Cren7-methylating activity of the S. islandicus cell extract by anti-aKMT antibodies. (A) Abundance of aKMT in S. islandicus. S. islandicus was grown to the exponential (E) or stationary (S) phase at 75° or 85°C. Samples were taken, centrifuged, and subjected to SDS-PAGE. aKMT was detected by immunoblotting using anti-aKMT antibodies. (B and C) Inhibition by anti-aKMT antibodies of the ability of recombinant aKMT and the S. islandicus cell extract to methylate recombinant Cren7. A sample of the S. islandicus cell extract or recombinant aKMT at a concentration similar to that in the extract was incubated with recombinant Cren7 and [³H]SAM in the presence of increasing amounts of anti-aKMT antibodies. Methyl transfer to Cren7 was determined by fluorography (B) and liquid scintillation counting (C). Reaction mixtures containing recombinant aKMT and the cell extract are shown in gray and white, respectively, in the fluorogram (C). All numbers are the averages of three independent measurements.