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Structural modeling of human DHFR in different ligand bound states
Author(s) -
May James,
Reed Colin,
Bargman Jerrod,
Huettig Emma,
Chowdhury Parag,
Bhabha Gira
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.lb167
Subject(s) - dihydrofolate reductase , active site , enzyme , stereochemistry , biochemistry , chemistry
Understanding the functional differences between bacterial and human enzymes is critical for the development of novel antibiotics to specifically target bacterial pathogens. Dihydrofolate Reductase (DHFR) is a ubiquitous enzyme present in both bacteria and humans that reduces dihydrofolate to tetrahydrofolate, which is a precursor for thymidylate synthesis, and is therefore essential for cell growth. For this reason, DHFR has been a focus in anticancer and antibiotic drug development. Crystollographic and NMR studies have elucidated how the E. coli human enzymes work. The E. coli enzyme undergoes large conformational changes in the active site loops as it progresses through the catalytic cycle. In contrast, the active site loops in the human enzyme are more rigid, and the enzyme undergoes a twisting hinge motion to accommodate ligand flux. We compared two human DHFR (hDHFR) crystal structures; one with hDHFR bound to NADPH, and the other model showing hDHFR bound to both the folic acid and NADP + . hDHFR:NADPH shows the active site with the hinge open. hDHFR:NADP + :folic acid shows the enzyme with the hinge closed, and the active site prepared for catalysis. Using 3D printing technology, we modeled these two conformations of hDHFR. These mechanistic differences between bacterial and human DHFRs can be utilized to design more specifically targeted antibiotics. Supported by a grant from HHMI Pre‐College Program.