PMID:9374515

Citation	Whitlow, M, Howard, AJ, Stewart, D, Hardman, KD, Kuyper, LF, Baccanari, DP, Fling, ME and Tansik, RL (1997) X-ray crystallographic studies of Candida albicans dihydrofolate reductase. High resolution structures of the holoenzyme and an inhibited ternary complex. J. Biol. Chem. 272:30289-98
Abstract	The recent rise in systemic fungal infections has created a need for the development of new antifungal agents. As part of an effort to provide therapeutically effective inhibitors of fungal dihydrofolate reductase (DHFR), we have cloned, expressed, purified, crystallized, and determined the three-dimensional structure of Candida albicans DHFR. The 192-residue enzyme, which was expressed in Escherichia coli and purified by methotrexate affinity and cation exchange chromatography, was 27% identical to human DHFR. Crystals of C. albicans DHFR were grown as the holoenzyme complex and as a ternary complex containing a pyrroloquinazoline inhibitor. Both complexes crystallized with two molecules in the asymmetric unit in space group P21. The final structures had R-factors of 0.199 at 1.85-A resolution and 0.155 at 1.60-A resolution, respectively. The enzyme fold was similar to that of bacterial and vertebrate DHFR, and the binding of a nonselective diaminopyrroloquinazoline inhibitor and the interactions of NADPH with protein were typical of ligand binding to other DHFRs. However, the width of the active site cleft of C. albicans DHFR was significantly larger than that of the human enzyme, providing a basis for the design of potentially selective inhibitors.
Links	PubMed
Keywords	Amino Acid Sequence; Candida albicans/enzymology; Crystallography, X-Ray; Fungal Proteins/ultrastructure; Humans; Hydrogen Bonding; Molecular Sequence Data; NADP/chemistry; Recombinant Proteins; Sequence Alignment; Tetrahydrofolate Dehydrogenase/ultrastructure
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
CANAX:DYR	Contributes to	GO:0004146: dihydrofolate reductase activity	ECO:0000247:	PMID:9374515 SGD:DFR1	F		The HHpred predicted E-value for this is 1.2E-32. In the literature Fig. 1 compares Candida albicans' Dihydrofolate Reductase to Pneumocystis carinii and they share a 34% match with each other's amino acid sequence. The activity also matches the yeast gene DFR1.	complete CACAO 12630

References

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