Figure 4
Binding modes of pemetrexed (left) and raltitrexed (right) in the active sites of the TS (top) and DHFR (bottom) subunits of BbDHFRTS. Active sites from protomer A (TS, violet; DHFR, green; ligands, white) are overlaid with active sites from protomer B (TS, yellow; DHFR, pink; ligands, black) for both complexes. Raltitrexed (RTX) and pemetrexed (PTX) bind the TS active site identically in both protomers of both structures. For the DHFR subunit, the glutamate tail of PTX is consistent across both protomers of 3k2h
, creating a salt bridge with Arg83. The glutamate tail of RTX is rotated relative to PTX in the DHFR subunit, resulting in loss of the Arg83 salt bridge, and binds in different conformations to each protomer of 3nrr
. This figure was created using PyMOL (DeLano, 2002). |