with the highest flexibility in correspondence
of the loops L23 (residues 49–53), and L45 (79–82).
The replacement of Y65 in the original structure with an arginine
residue has only a moderate effect on the local motions. This residue
is in fact located at the C-terminal portion of the b3 strand,
flanking the loop L34, and does not appear to be vital for the conservation
of the protein fold. In the mutant, the side chain of R65
can in fact dynamically interact with the carboxylic oxygen from
the backbone of D68 through a hydrogen bond with a 64.6% occupancy
(Fig. 4B), but this only leads to a slight difference over time
of the position of L34 from the experimental data collected on
MNEI, with a minimal impact on the motion of the area, as
observed in the RMSF plot.
This interaction is in agreement with the chemical shift differences
previously observed in the 2D NMR analysis reported in
Fig. 2.