(A) Superimposition of the crystal structure of MTHFD2/15/21 (PDB 7EHM) on MTHFD2/3/21 (PDB 7EHV).
For clarity, compound 21 is omitted in the figure. Red
dashed lines indicate the
hydrogen-bond and green ones indicate the π–π interactions.
The tail group of 3 loses the important hydrogen-bond
network with MTHFD2 in comparison with 15 and therefore
weakens its inhibition toward MTHFD2. (B) and (C) Superimposition
of the crystal structure of MTHFD2/15/21 (PDB 7EHM)
on MTHFD2/9/21 (PDB 7EHN). (C) is the view
of (B) after 60° rotation along the X-axis followed
by 35° rotation along the Y-axis. For clarity,
compound 21 is omitted in the figure. Red and black dashed
lines indicate the hydrogen bond. In (B), the tail group of 9 loses the hydrogen-bond network with MTHFD2 and, instead
of direct interactions with Glu141 as observed in 15,
the core of 9 forms the hydrogen-bond interaction with
Glu141 through a water molecule. In (C), in comparison with 15 (yellow), the indole group of 9 (magenta)
forms shape complementarity interactions with MTHFD2 and makes the
additional hydrogen-bond interaction with Asn204.