[Assignment, by proton magnetic resonance, of histidines of dihydrofolate reductase from chicken liver]. / Affectation, par résonance magnétique de protons, des histidines de la dihydrofolate réductase de foie de poulet.
C R Acad Sci III
; 304(2): 55-60, 1987.
Article
in Fr
| MEDLINE
| ID: mdl-3101992
ABSTRACT
The effects of pH and temperature upon C epsilon 1 H resonances of the four histidyl residues of chicken liver dihydrofolate reductase in binary complex with methotrexate were studied by 500-MHz 1H NMR spectroscopy. The four histidines labelled a, b, c, d are distinguishable by their pK values and the chemical shifts of their C epsilon 1H protons. The local electromagnetic environment as deduced from X-ray studies at 2.9 A resolution was used as a basis for proposed assignment of the four histidines. The assignments were a H42, b H140, c H131, d H87. Furthermore the histidyl residue labelled c was shown to be upfield shifted in its C epsilon 1H proton in the enzyme-methotrexate complex compared to the native enzyme. The hypothesis of a conformational change of the protein is discussed.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Tetrahydrofolate Dehydrogenase
/
Histidine
/
Liver
Limits:
Animals
Language:
Fr
Journal:
C R Acad Sci III
Year:
1987
Document type:
Article