Figure 5

MTX and PTX binding by SHMTs. Green mesh (in A,C,E,G,I) represents Polder electron density maps contoured at 4.5 σ calculated for 5 Å volume around the antifolates. Panels (B,D,F,H,J) show networks of interactions between SHMTs and antifolates. Internal (LLP) or external aldimines are yellow, free serine is in magenta, residues from another protein subunit than indicated in caption, involved in interactions with MXT or PTX, are marked by asterisks.