Vibrational Structure of Dihydrofolate Bound to R67 Dihydrofolate Reductase

Hua Deng, Robert Callender, Elizabeth Howell

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

R67 is a Type II dihydrofolate reductase (DHFR) that catalyzes the reduction of dihydrofolate (DHF) to tetrahydrofolate by facilitating the addition of a proton to N5 of DHF and the transfer of a hydride ion from NADPH to C6. Because this enzyme is a plasmid-encoded DHFR from trimethoprim-resistant bacteria, extensive studies on R67 with various methods have been performed to elucidate its reaction mechanism. Here, Raman difference measurements, conducted on the ternary complex of R67·NADP +·DHF believed to be an accurate mimic of the productive DHFR·NADPH·DHF complex, show that the pKa of N5 in the complex is less than 4. This is in clear contrast to the behavior observed in Escherichia coli DHFR, a substantially more efficient enzyme, where the pK a of bound DHF at N5 is increased to 6.5 compared with its solution value of 2.6. A comparison of the ternary complexes in R67 and E. coli DHFRs suggests that enzymic raising of the pKa at N5 can significantly increase the catalytic efficiency of the hydride transfer step. However, R67 shows that even without such a strategy an effective DHFR can still be designed.

Original languageEnglish (US)
Pages (from-to)48956-48960
Number of pages5
JournalJournal of Biological Chemistry
Volume276
Issue number52
DOIs
StatePublished - Dec 28 2001

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Tetrahydrofolate Dehydrogenase
Hydrides
Escherichia coli
Trimethoprim
Enzymes
NADP
Protons
Bacteria
Plasmids
Ions
dihydrofolate

ASJC Scopus subject areas

  • Biochemistry

Cite this

Vibrational Structure of Dihydrofolate Bound to R67 Dihydrofolate Reductase. / Deng, Hua; Callender, Robert; Howell, Elizabeth.

In: Journal of Biological Chemistry, Vol. 276, No. 52, 28.12.2001, p. 48956-48960.

Research output: Contribution to journalArticle

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