A noncatalytic tetrahydrofolate tight binding site is on the small domain of 10-formyltetrahydrofolate dehydrogenase.

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Fu TF, Maras B, Barra D, Schirch V

A noncatalytic tetrahydrofolate tight binding site is on the small domain of 10-formyltetrahydrofolate dehydrogenase.

Arch Biochem Biophys. 1999 Jul 15;367(2):161-6.

PubMed ID

10395731 [ View in PubMed

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Abstract

10-Formyltetrahydrofolate dehydrogenase has previously been identified as a tight binding protein of the polyglutamate forms of tetrahydrofolate (R. J. Cook and C. Wagner, Biochemistry 21, 4427-4434, 1982). Each subunit contains two independently folded domains connected by a linking peptide. By using the stable substrate and product analogs 10-formyl 5,8-dideazafolate and 5, 8-dideazafolate, respectively, we have determined that the tight binding folate site is separate from the catalytic site and that it is located on the N-terminal domain of the protein. This was achieved by cross-linking 10-formyl 5,8-dideazafolate to the dehydrogenase through the carboxyl group of the substrate analog. The cross-linked substrate analog was converted to the cross-linked product complex by adding either NADP+ or 2-mercaptoethanol, proving that the 10-formyl 5,8-dideazafolate was bound at the active site. With the active site cross-linked to 5,8-dideazafolate and not available for binding, the enzyme still bound 5, 8-dideazafolate-[3H]tetraglutamate tightly but noncovalently. Separation of the large and small domains by limited proteolysis showed that the tightly bound 5,8-dideazafolate-[3H]tetraglutamate was located on the small domain. The location of the cross-linked 10-formyl 5,8-dideazafolate at the active site was determined by amino acid sequencing of an isolated tryptic peptide.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Tetrahydrofolic acid	Cytosolic 10-formyltetrahydrofolate dehydrogenase	Protein	Humans	Unknown	Cofactor	Details