Figure 5.
FIGURE 5. Crystal structures of an interacting
with either UUA or UUG in the ribosomal A-site. A, unbiased
difference Fourier electron density maps for ASL and mRNA (green
mesh) are shown in stereo for the complex with the UUA codon.
The 5' part of the ASL up to and including parts of U33 is not
visible. B, the same as A but for the complex having a UUG codon
in the A-site. C, the m^5U-A base pair along
with unbiased difference Fourier electron density maps (green
mesh). The base pair refined into a position with slightly
distorted WC geometry. Weak density for the sulfonic acid group
was visible at this level. D, the m^5U·G base pair
with unbiased difference Fourier electron density maps (green
mesh). Although the density is not very strong, it can be
excluded that the base pair adopts G·U wobble geometry
(compare modeled G·U base pair in transparent gray with
electron density maps). E, comparison of stacking interaction
between a modeled G·U wobble base pair and the m^5U·G base pair.
The modified uridine has a more favorable stacking interaction
with A35 than an unmodified base would have.
The above figure is reprinted
by permission from the ASBMB:
J Biol Chem
(2008,
283,
18801-18811)
copyright 2008.
interacting
with either UUA or UUG in the ribosomal A-site. A, unbiased
difference Fourier electron density maps for ASL and mRNA (green
mesh) are shown in stereo for the complex with the UUA codon.
The 5' part of the ASL up to and including parts of U33 is not
visible. B, the same as A but for the complex having a UUG codon
in the A-site. C, the 
m^5U-A base pair along
with unbiased difference Fourier electron density maps (green
mesh). The base pair refined into a position with slightly
distorted WC geometry. Weak density for the sulfonic acid group
was visible at this 
level. D, the