New insights into DHFR interactions: Analysis of Pneumocystis carinii and mouse DHFR complexes with NADPH and two highly potent 5‐(ω‐carboxy(alkyloxy) trimethoprim derivatives reveals conformational correlations with activity and novel parallel ring stacking interactions

  title={New insights into DHFR interactions: Analysis of Pneumocystis carinii and mouse DHFR complexes with NADPH and two highly potent 5‐($\omega$‐carboxy(alkyloxy) trimethoprim derivatives reveals conformational correlations with activity and novel parallel ring stacking interactions},
  author={Vivian Cody and Jim Pace and Kim Chisum and Andre Rosowsky},
  journal={Proteins: Structure},
Structural data are reported for two highly potent antifolates, 2,4‐diamino‐5‐[3′,4′‐dimethoxy‐5′‐(5‐carboxy‐1‐pentynyl)]benzylpyrimidine (PY1011), with 5000‐fold selectivity for Pneumocystis carinii dihydrofolate reductase (pcDHFR), relative to rat liver DHFR, and 2,4‐diamino‐5‐[2‐methoxy‐5‐(4‐carboxybutyloxy)benzyl]pyrimidine (PY957), that has 80‐fold selectivity for pcDHFR. Crystal structures are reported for NADPH ternary complexes with PY957 and pcDHFR, refined to 2.2 Å resolution; with… 
Structural analysis of Pneumocystis carinii and human DHFR complexes with NADPH and a series of five potent 6-[5'-(ω-carboxyalkoxy)benzyl]pyrido[2,3-d]pyrimidine derivatives.
  • V. Cody, J. Pace
  • Chemistry
    Acta crystallographica. Section D, Biological crystallography
  • 2011
Structural results suggest that the weaker binding of this series compared with that of their pyrimidine homologs in part arises from the flexibility observed in their side-chain conformations, which do not optimize intermolecular contact to Arg75.
Structural analysis of Pneumocystis carinii dihydrofolate reductase complexed with NADPH and 2,4-diamino-6-[2-(5-carboxypent-1-yn-1-yl)-5-methoxybenzyl]-5-methylpyrido[2,3-d]pyrimidine.
  • V. Cody, J. Pace, E. Stewart
  • Chemistry
    Acta crystallographica. Section F, Structural biology and crystallization communications
  • 2012
In inhibition data, the greater selectivity for pcDHFR compared with mammalian DHFR of these inhibitors is also influenced by the enhanced hydrophobic interactions of the side-chain methylene atoms with Phe69 of pcDH FR compared with Asn64 of mammalianDHFR.
Kinetic and Structural Analysis for Potent Antifolate Inhibition of Pneumocystis jirovecii, Pneumocystis carinii, and Human Dihydrofolate Reductases and Their Active-Site Variants
ABSTRACT A major concern of immunocompromised patients, in particular those with AIDS, is susceptibility to infection caused by opportunistic pathogens such as Pneumocystis jirovecii, which is a
Crystal Structure of Bacillus anthracis Dihydrofolate Reductase with the Dihydrophthalazine-Based Trimethoprim Derivative RAB1 Provides a Structural Explanation of Potency and Selectivity
This work has synthesized one compound (RAB1) displaying favorable 50% inhibitory concentration (54 nM) and MIC (≤12.8 μg/ml) values and binding of RAB1 causes a conformational change of the side chain of Arg58 and Met37 to accommodate the dihydrophthalazine moiety.
Correlations of inhibitor kinetics for Pneumocystis jirovecii and human dihydrofolate reductase with structural data for human active site mutant enzyme complexes.
Structural and mutagenesis data support the hypothesis that the enhanced selectivity of PY957 for pcDHFR is in part due to the contributions at positions 37 and 69 (pcDHFR numbering).
Elucidating features that drive the design of selective antifolates using crystal structures of human dihydrofolate reductase.
Five crystal structures of human DHFR bound to a new class of antimicrobial agents, the propargyl-linked antifolates (PLAs), with a range of potency reveal that interactions between the ligands and Asn 64, Phe 31, and Phe 34 are important for increased affinity for human DH FR and that loop residues 58-64 undergo ligand-induced conformational changes.
Design, synthesis, and molecular modeling of novel pyrido[2,3-d]pyrimidine analogues as antifolates; application of Buchwald-Hartwig aminations of heterocycles.
A novel series of pyrido[2,3-d]pyrimidines as selective and potent DHFR inhibitors against these opportunistic infections are presented and Buchwald-Hartwig coupling reaction of substituted anilines with pivaloyl protected 2,4-diamino-6-bromo-pyrimidine was successfully explored to synthesize these analogues.


Structure-based enzyme inhibitor design: modeling studies and crystal structure analysis of Pneumocystis carinii dihydrofolate reductase ternary complex with PT653 and NADPH.
Homology-modeling studies of the tgDHFR structure suggest that differences in ligand-binding orientation and enzyme sequence could influence the enhanced selectivity of PT653 for tgHRF, and hydrophobic analogs could be used as lead compounds in the design of more pcDHFR-selective antifolates.
Structural studies on bioactive compounds. 30. Crystal structure and molecular modeling studies on the Pneumocystis carinii dihydrofolate reductase cofactor complex with TAB, a highly selective antifolate.
These results confirm prior molecular modeling investigations of the binding of TAB to pcDHFR that identified four low-energy binding geometries, two involving rotations about the terminal N(2)-N(3) triazenyl linkage and two involving atropisomerism about the pivotal pyrimethamine-phenyl bond.
Structure determination of tetrahydroquinazoline antifolates in complex with human and Pneumocystis carinii dihydrofolate reductase: correlations between enzyme selectivity and stereochemistry.
Comparison of the Toxoplasma gondii DHFR (tgDHFR) sequence with those of other DHFRs provides insight into the role of sequence and conformation in inhibitor-binding preferences which may aid in the design of novel antifolates with specific DHFR selectivity.
Inhibition of Pneumocystis carinii, Toxoplasma gondii, and Mycobacterium avium dihydrofolate reductases by 2,4-diamino-5-[2-methoxy-5-(omega-carboxyalkyloxy)benzyl]pyrimidines: marked improvement in potency relative to trimethoprim and species selectivity relative to piritrexim.
Compound 3g may be viewed as a promising lead in the search for new antifolates with potential clinical activity against P. carinii and other opportunistic pathogens in patients with AIDS.
Ligand-induced conformational changes in the crystal structures of Pneumocystis carinii dihydrofolate reductase complexes with folate and NADP+.
The larger binding site access in the new "flap-open" loop 23 conformation of the binary FA FA complex is consistent with the rapid release of cofactor from the product complex during catalysis as well as the more rapidrelease of substrate product from the binary complex as a result of the weaker contacts of the closed loop 24 conformation.
Analysis of quinazoline and pyrido[2,3-d]pyrimidine N9-C10 reversed-bridge antifolates in complex with NADP+ and Pneumocystis carinii dihydrofolate reductase.
The results suggest that the loss of hydrogen-bonding interactions with N8 is more important to potency than the interactions of the methoxybenzyl substituents in pcDHFR.
Understanding the role of Leu22 variants in methotrexate resistance: comparison of wild-type and Leu22Arg variant mouse and human dihydrofolate reductase ternary crystal complexes with methotrexate and NADPH.
The unexpected results from this comparison of the mouse and human DHFR complexes bound with the same ligand and cofactor illustrate the importance of detailed study of several species of enzyme, even when there is a high sequence homology between them.
Further studies on 2,4-diamino-5-(2',5'-disubstituted benzyl)pyrimidines as potent and selective inhibitors of dihydrofolate reductases from three major opportunistic pathogens of AIDS.
The results suggest that it may be possible to develop clinically useful nonclassical antifolates that are both potent and selective against the major opportunistic pathogens of AIDS.
Three-dimensional structure of M. tuberculosis dihydrofolate reductase reveals opportunities for the design of novel tuberculosis drugs.
The crystal structure of dihydrofolate reductase from Mycobacterium tuberculosis, a human pathogen responsible for the death of millions of human beings per year, is reported and it is indicated that the overall protein folds are similar, but that the environments of both NADP and of the inhibitors contain interesting differences between the enzymes from host and pathogen.