Inhibitory complexes of N10-formyltetrahydrofolate synthetase indicate negative cooperativity between subunits
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چکیده
منابع مشابه
Distribution of 10-formyltetrahydrofolate synthetase in eubacteria.
The distribution of 10-formyltetrahydrofolate synthetase, which activates formate for use as a one-carbon donor in a variety of biosynthetic reactions, was determined for a variety of eubacteria. Organisms from several genera were found to lack detectable synthetase activity; however, all organisms tested were found to contain 5,10-methylenetetrahydrofolate dehydrogenase activity.
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Binding of Mn(pi)-nucleotide complexes to the enzyme formyltertrahydrofolate synthetase (EC 6.3.4.3) from Clostridium cylindrosporum has been examined in the presence and absence of other substrates by solvent proton relaxation mearurements. MnADP and MnATP form ternary complexes with the enzyme with highly enhanced proton relaxation rates for water. The enhancement parameters, epsilont, for th...
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Formyltetrahydrofolate synthetase undergoes inactivation at pH values below 7. Inactivation is accompanied by both the dissociation of the tetramer into monomers and the exposure of aromatic amino acids to the solvent. The rate of inactivation is a function of pH. This rate and the rate of exposure of tryptophan residues to the aqueous environment follow first order kinetics. After prolonged in...
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The hydrodynamic parameters of the thermostable formyltetrahydrofolate synthetase from Clostridium thermoaceticum have been measured in the ultracentrifuge at 20”. &J,~ = 9.86 f 0.20 S;vzo = 0.752 f 0.011 cc per g; and molecular weight = 244,000 f 9,000. Calculations based on these parameters give a frictional ratio, f/f0 = 1.27 f 0.11, and a Stokes radius of 53.0 f 4.8 A. The sedimentation con...
متن کاملChloroplast Glutamine Synthetase, the Key Regulator of Nitrogen Metabolism in Wheat, Performs Its Role by Fine Regulation of Enzyme Activity via Negative Cooperativity of Its Subunits
Glutamine synthetase (GS) is of central interest as the main route of ammonia assimilation in plants, and as a connection point between the organic and inorganic worlds. Even though GS activity is critical for producing high yields of crop plants, the autoregulation of substrate consumption of wheat GS remained unknown until now. Here we show kinetic evidence, that the chloroplast localized GS ...
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ژورنال
عنوان ژورنال: Acta Crystallographica Section A Foundations of Crystallography
سال: 2006
ISSN: 0108-7673
DOI: 10.1107/s0108767306097078