Proton Magnetic Resonance Studies of Folate, Dihydrofolate, and Methotrexate
نویسندگان
چکیده
منابع مشابه
Nuclear Magnetic Resonance Studies of the Dihydrofolate Reductase-Nicotinamide Adenine Dinucleotide Phosphate-Folate Complex: Characterization of Three Coexisting Conformational Statest
The Lactobacillus casei dihydrofolate reductase-folateNADP+ complex is shown by ‘H and 13C NMR to exist in three interconverting conformational states, I, IIa, and IIb. The proportions of the three states, as estimated from the intensities of the three separate 13C resonances observed in the complex containing [3-~arboxamido-’~C]NADP+, are pH dependent. State I predominates at low pH and states...
متن کاملCarbon-13 magnetic resonance evaluation of polypeptide secondary structure and correlation with proton magnetic resonance studies.
With the use of appropriately chosen solvent pairs it is demonstrated that solvent dependence of peptide carbonyl carbon resonances can be correlated with polypeptide secondary structure. Solvent titrations show the peptide carbonyl which is intramolecularly hydrogen bonded to exhibit less chemical shift on going from a dimethylsulfoxide solution to a solution containing a solvent which is a go...
متن کاملProton nuclear magnetic resonance studies of isonitrile-heme protein complexes.
Steric interactions between bound ligand molecules and the valine E11 methyl groups of human hemoglobin and sperm whale myoglobin have been examined directly by high resolution NMR techniques. The methyl proton resonances of this amino acid are shifted markedly upfield and away from the bulk of the protein resonances by the shielding effect of circulating pi electrons in the porphyrin ring. We ...
متن کاملProton magnetic resonance studies of ultraviolet-irradiated apurinic acid.
In apurinic acid, a single-stranded polydeoxyribonucleotide easily obtained upon depurination of DNA, the proton resonances arising from thymine and cytosine are readily observable in aqueous solution of 25 degrees C. Two methyl thymine resonances, centered at 1.88 ppm and separated by 0.045 ppm, are observed. We attribute the downfield methyl resonance to thymines with no pyrimidine nearest ne...
متن کاملProton magnetic resonance studies of Chromatium high-potential iron protein.
Contact-shifted nuclear magnetic resonances, arising from molecular paramagnetism, have been observed in both reduced and oxidized forms of the high-potential iron protein (HiPIP) isolated from Chromatium. Contact shifts of the reduced, formally diamagnetic form increase with temperature, indicating antiferromagnetic exchange coupling of the component iron atoms with thermal population of a mag...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1973
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(19)43355-3