Figure 3.
The labeling and base coloring scheme are consistent with
that in Figure 1. (a) Stereo view of the SAM binding site in the
S[MK] box riboswitch. The adenosine moiety of SAM is shown to
base-stack between U72 and G90. (b) The A73 circle
G90-C35 base triple paves the 'floor' of the SAM binding pocket.
The C-G base pair is co-planar, whereas A73 contacts from the
minor groove of G90 at a 45° tilted angle, which orients N6
of A73 for SAM recognition one base plane above.
circle
G90-C35 base triple paves the 'floor' of the SAM binding pocket.
The C-G base pair is co-planar, whereas A73 contacts from the
minor groove of G90 at a 45° tilted angle, which orients N6
of A73 for SAM recognition one base plane above.