15N and 1H NMR evidence for multiple conformations of the complex of dihydrofolate reductase with its substrate, folate

[摘要]

The binding of folate to Lactobacillus casei dihydrofolate reductase in the presence and absence of NADP⁺ has been studied by ¹⁵N NMR, using [5-¹⁵N]folate. In the presence of NADP⁺, three separate signals were observed for the single ¹⁵N atom, in agreement with our earlier evidence from ¹H and ¹³C NMR for multiple conformations of this complex [(1982) Biochemistry 21, 5831–5838]. The ¹⁵N spectra of the binary enzymefolate complex provide evidence for the first time that this complex also exists in at least two conformational states. This is confirmed by the observation of two separate resonances for the 7-proton of bound folate, located by two-dimensional exchange spectroscopy.

[学科分类] 生物化学/生物物理

[关键词] Dihydrofolate reductase;Folate;15N-NMR;2D NMR