Preliminary Crystallographic Data for Pneumocystis carinii Dihydrofolate Reductase

Stammers, D.K.; Delves, C. J.; Ballantine, Stuart P.; Jones, E Y; Stuart, David I.; Achari, Aniruddha; Bryant, P.K.; Champness, J.N.

doi:10.1006/jmbi.1993.1183

Cited by 5 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Purification of P. carinii DHFR has been described by Delves et al [5]. Crystals were grown as described previously [11], either as a binary complex in the presence of cofactor NADPH alone (holoenzyme) or as a ternary complex in the presence of NADPH and inhibitor (either trimethoprim or piritrexim). X-ray data were collected on a Siemens threecircle camera and multiwire counter area detector system.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The structure of Pneumocystis carinii dihydrofolate reductase to 1.9 å resolution

et al. 1994

View full text Add to dashboard Cite

These structures show how two drugs interact with a fungal DHFR. A comparison of the three-dimensional structure of this relatively large DHFR with bacterial or mammalian enzyme-inhibitor complexes determined previously highlights some additional secondary structure elements in this particular enzyme species. These comparisons provide further insight into the principles governing DHFR-inhibitor interaction, in which the volume of the active site appears to determine the strength of inhibitor binding.

show abstract

Section: Methodsmentioning

confidence: 99%

“…The enzyme is found almost exclusively in inclusion bodies which, following initial solubilization in guanidinium hydrochloride, can be refolded to give a fully active enzyme which is kinetically indistinguishable from soluble enzyme. We have shown that this enzyme gives well ordered crystals that diffract to beyond 2 A resolution [11].…”

Section: Introductionmentioning

confidence: 92%

The structure of Pneumocystis carinii dihydrofolate reductase to 1.9 å resolution

et al. 1994

View full text Add to dashboard Cite

show abstract

“…A crystal structure of the ternary complex of PTX and TMP with NADPH and P. carinii DHFR had already been reported by Champness and co-workers 22,23 when this work began, but unfortunately the three-dimensional (3D) coordinates of the ternary complex with PTX were not in the public domain. PTX and TMP, according to the published information, bind similarly to the active site, the most notable difference being a conformational change of the Phe69 side chain in the case of the PTX complex, resulting in a face-edge interaction with the dimethoxybenzyl group that was absent in the case of the TMP complex.…”

Section: Molecular Modelingmentioning

confidence: 99%

“…Interest in this previously unknown compound was prompted by a desire to ascertain how removal of the putative out-ofplane hydrophobic interaction of the 4′-methoxy group in 3 might influence selectivity against P. carinii, T. gondii, and M. avium DHFR vs rat DHFR. Compound 22 may be viewed as an analogue of brodimoprim (23), which was initially reported to have some advantages over TMP but was subsequently withdrawn from the market. 9,10…”

Section: Introductionmentioning

confidence: 99%

Design, Synthesis, and Antifolate Activity of New Analogues of Piritrexim and Other Diaminopyrimidine Dihydrofolate Reductase Inhibitors with ω-Carboxyalkoxy or ω-Carboxy-1-alkynyl Substitution in the Side Chain

Chan

Forsch

et al. 2005

J. Med. Chem.

View full text Add to dashboard Cite

As part of a search for dihydrofolate reductase (DHFR) inhibitors combining the high potency of piritrexim (PTX) with the high antiparasitic vs mammalian selectivity of trimethoprim (TMP), the heretofore undescribed 2,4-diamino-6-(2',5'-disubstituted benzyl)pyrido[2,3-d]pyrimidines 6-14 with O-(omega-carboxyalkyl) or omega-carboxy-1-alkynyl groups on the benzyl moiety were synthesized and tested against Pneumocystis carinii, Toxoplasma gondii, and Mycobacterium avium DHFR vs rat DHFR. Three N-(2,4-diaminopteridin-6-yl)methyl)-2'-(omega-carboxy-1-alkynyl)dibenz[b,f]azepines (19-21) were also synthesized and tested. The pyridopyrimidine with the best combination of potency and selectivity was 2,4-diamino-5-methyl-6-[2'-(5-carboxy-1-butynyl)-5'-methoxy]benzyl]pyrimidine (13), with an IC(50) value of 0.65 nM against P. carinii DHFR, 0.57 nM against M. avium DHFR, and 55 nM against rat DHFR. The potency of 13 against P. carinii DHFR was 20-fold greater than that of PTX (IC(50) = 13 nM), and its selectivity index (SI) relative to rat DHFR was 85, whereas PTX was nonselective. The activity of 13 against P. carinii DHFR was 20 000 times greater than that of TMP, with an SI of 96, whereas that of TMP was only 14. However 13 was no more potent than PTX against M. avium DHFR, and its SI was no better than that of TMP. Molecular modeling dynamics studies using compounds 10 and 13 indicated a slight binding preference for the latter, in qualitative agreement with the IC(50) data. Among the pteridines, the most potent against P. carinii DHFR and M. avium DHFR was the 2'-(5-carboxy-1-butynyl)dibenz[b,f]azepinyl derivative 20 (IC(50) = 2.9 nM), whereas the most selective was the 2'-(5-carboxy-1-pentynyl) analogue 21, with SI values of >100 against both P. carinii and M. avium DHFR relative to rat DHFR. The final compound, 2,4-diamino-5-[3'-(4-carboxy-1-butynyl)-4'-bromo-5'-methoxybenzyl]pyrimidine (22), was both potent and selective against M. avium DHFR (IC(50) = 0.47 nM, SI = 1300) but was not potent or selective against either P. carinii or T. gondii DHFR.

show abstract

Untitled

Polshakov¹,

Smirnov²,

Birdsall

et al. 2002

Journal of Biomolecular NMR

View full text Add to dashboard Cite

Preliminary Crystallographic Data for Pneumocystis carinii Dihydrofolate Reductase

Cited by 5 publications

References 0 publications

The structure of Pneumocystis carinii dihydrofolate reductase to 1.9 å resolution

The structure of Pneumocystis carinii dihydrofolate reductase to 1.9 å resolution

Design, Synthesis, and Antifolate Activity of New Analogues of Piritrexim and Other Diaminopyrimidine Dihydrofolate Reductase Inhibitors with ω-Carboxyalkoxy or ω-Carboxy-1-alkynyl Substitution in the Side Chain

Untitled

Contact Info

Product

Resources

About