%0 Journal Article
%A Lamb, Kristen
M.
%A G-Dayanandan, Narendran
%A Wright, Dennis L.
%A Anderson, Amy C.
%D 2016
%T Elucidating Features That Drive the Design of Selective
Antifolates Using Crystal Structures of Human Dihydrofolate Reductase
%U https://acs.figshare.com/articles/journal_contribution/Elucidating_Features_That_Drive_the_Design_of_Selective_Antifolates_Using_Crystal_Structures_of_Human_Dihydrofolate_Reductase/2366398
%R 10.1021/bi400852h.s001
%2 https://acs.figshare.com/ndownloader/files/4005847
%K residues Ile 121
%K ligand
%K Staphylococcus aureus DHFR
%K Phe 34. Synthesis
%K Candida glabrata DHFR
%K target dihydrofolate reductase
%K IC 50 values
%K Human Dihydrofolate ReductaseThe pursuit
%K residues Phe 92
%K PLA
%K guide antimicrobial antifolate development
%K Val 115
%X The pursuit of antimicrobial drugs
that target dihydrofolate reductase
(DHFR) exploits differences in sequence and dynamics between the pathogenic
and human enzymes. Here, we present five crystal structures of human
DHFR bound to a new class of antimicrobial agents, the propargyl-linked
antifolates (PLAs), with a range of potency (IC50 values
of 0.045–1.07 μM) for human DHFR. These structures reveal
that interactions between the ligands and Asn 64, Phe 31, and Phe
34 are important for increased affinity for human DHFR and that loop
residues 58–64 undergo ligand-induced conformational changes.
The utility of these structural studies was demonstrated through the
design of three new ligands that reduce the number of contacts with
Asn 64, Phe 31, and Phe 34. Synthesis and evaluation show that one
of the designed inhibitors exhibits the lowest affinity for human
DHFR of any of the PLAs (2.64 μM). Comparisons of structures
of human and Staphylococcus aureus DHFR bound to
the same PLA reveal a conformational change in the ligand that enhances
interactions with residues Phe 92 (Val 115 in huDHFR) and Ile 50 (Ile
60 in huDHFR) in S. aureus DHFR, yielding selectivity.
Likewise, comparisons of human and Candida glabrata DHFR bound to the same ligand show that hydrophobic interactions
with residues Ile 121 and Phe 66 (Val 115 and Asn 64 in human DHFR)
yield selective inhibitors. The identification of residue substitutions
that are important for selectivity and the observation of active site
flexibility will help guide antimicrobial antifolate development for
the inhibition of pathogenic species.
%I ACS Publications