On the mechanism of ribonucleoside triphosphate reductase from Lactobacillus leichmannii. Evidence for 3' C--H bond cleavage.

نویسندگان

  • J Stubbe
  • D Ackles
  • R Segal
  • R L Blakley
چکیده

The 3' carbon-hydrogen bond of [3'-3H]uridine 5'-triphosphate is is cleaved during its conversion to 2'-deoxyuridine 5'-triphosphate catalyzed by Lactobacillus leichmannii ribonucleoside triphosphate reductase. A selection against 3H of approximately 1.8 is observed on this reduction. During the course of this reaction, no 3H is released to the solvent, and no 3H is recovered in reisolated coenzyme B12. Incubation of [3'-2H]uridine 5'-triphosphate with enzyme resulted in production of 2'-deoxy[3'-2H]uridine 5'-triphosphate.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Binding of Cob(II)alamin to the adenosylcobalamin-dependent ribonucleotide reductase from Lactobacillus leichmannii. Identification of dimethylbenzimidazole as the axial ligand.

The ribonucleoside triphosphate reductase (RTPR) from Lactobacillus leichmannii catalyzes the reduction of nucleoside 5'-triphosphates to 2'-deoxynucleoside 5'-triphosphates and uses coenzyme B12, adenosylcobalamin (AdoCbl), as a cofactor. Use of a mechanism-based inhibitor, 2'-deoxy-2'-methylenecytidine 5'-triphosphate, and isotopically labeled RTPR and AdoCbl in conjunction with EPR spectrosc...

متن کامل

Recent advances in the chemistry of vitamin B 12 and vitamin B 12 model compounds: reductive cobalt-carbon bond cleavage reactions.

The cobalt—carbon bond in alkylcobaloximes and in alkylcobalt derivatives of related chelates is reductively cleaved by thiols in mildly acidic medium, or by carbon monoxide, dithionite and stannite in alkaline solution. The reductants interact initially by trans attack of the cobalt atom, followed by the rate-determining cleavage of the Co—C bond. Cobalt-bound methyl groups are converted into ...

متن کامل

Mechanism of ribonucleoside diphosphate reductase from Escherichia coli. Evidence for 3'-C--H bond cleavage.

Incubation of the pyrimidine [3'-3H]UDP with ribonucleotide reductase resulted in an isotope effect on the conversion to dUDP which varied as a function of pH and allosteric effectors (pH, kH/kT, effector): 6.6, 4.7, ATP; 7.6, 3.3, ATP; 7.6, 2.6, dATP; 7.6, 2.0, TTP; 8.4, 2.8, ATP. During this reaction 3H2O was also released. The lower the pH of the reaction, the larger the isotope effect, and ...

متن کامل

Active site of ribonucleoside diphosphate reductase from Escherichia coli. Inactivation of the enzyme by 2'-substituted ribonucleoside diphosphates.

Ribonucleoside diphosphate reductase is an allosteric enzyme consisting of two nonidentical subunits, proteins B1 and B2. B1 contains dithiols which participate in the oxidation-reduction reactions of electron transport, while B2 contains a free radical essential for activity. Ribonucleoside diphosphates are bound to B1 but not to B2. Addition of 2'-deoxy-2'-chloro ribonucleoside diphosphates t...

متن کامل

Active Site of Ribonucleoside Diphosphate Reductase from Escherichia coli

Ribonucleoside diphosphate reductase is an allosteric enzyme consisting of two nonidentical subunits, proteins Bl and B2. Bl contains dithiols which participate in the oxidation-reduction reactions of electron transport, while B2 contains a free radical essential for activity. Ribonucleoside diphosphates are bound to Bl but not to B2. Addition of 2’-deoxy-2’-chloro ribonucleoside diphosphates t...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • The Journal of biological chemistry

دوره 256 10  شماره 

صفحات  -

تاریخ انتشار 1981