Inactivation of the ribonucleoside triphosphate reductase from Lactobacillus leichmannii by 2 prime -chloro-2 prime -deoxyuridine 5 prime -triphosphate: A 3 prime -2 prime hydrogen transfer during the formation of 3 prime -keto-2 prime -deoxyuridine 5 prime -triphosphate

Journal Article · Tue Oct 04 00:00:00 EDT 1988 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00420a038· OSTI ID:7101096

Ashley, G W; Harris, G; Stubbe, J ^[1]

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1. Univ. of Wisconsin, Madison (USA)

The ribonucleoside triphosphate reductase of Lactobacillus leichmannii converts the substrate analogue 2{prime}-chloro-2{prime}-deoxyuridine 5{prime}-triphosphate (C1UTP) into a mixture of 2{prime}-deoxyuridine triphosphate (dUTP) and the unstable product 3{prime}-keto-2{prime}-deoxyuridine triphosphate (3{prime}-keto-dUTP). This ketone can be trapped by reduction with NaBH{sub 4}, producing a 4:1 mixture of xylo-dUTP and dUTP. When (3{prime}-{sup 3}H)C1UTP is treated with enzyme in the presence of NaBH{sub 4}, the isomeric deoxyuridines isolated after alkaline phosphatase treatment retained 15% of the {sup 3}H in C1UTP. Degradation of these isomeric nucleosides has established the location of the {sup 3}H in 3{prime}-keto-dUTP as predominantly 2{prime}(S). The xylo-dU had 98.6% of its label at the 2{prime}(S) position and 1.5% at 2{prime}(R). The isolated dU had 89.6% of its label at 2{prime}(S) and 1.4% at 2{prime}(R), with the remaining 9% label inferred to be at the 3{prime}-carbon, this resulting from the direct enzymic production of dUTP. These results are consistent with enzymic production of a 1:1,000 mixture of dUTP and 3{prime}-keto-dUTP, where the 3{prime}-hydrogen of C1UTP is retained at 3{prime} during production of dUTP and is transferred to 2{prime}(S) during production of 3{prime}-keto-dUTP. The implications of these results and the unique role of the cofactor adenosylcobalamin are discussed in terms of reductase being a model for the B{sub 12}-dependent rearrangement reactions.

• OSTI ID: 7101096
• Journal Information: Biochemistry; (USA), Vol. 27:20; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
DNA REPLICATION
BIOCHEMISTRY
NUCLEOTIDE DEHYDROGENASES
INACTIVATION
RIBOSIDES
BIODEGRADATION
TRITIUM COMPOUNDS
DEOXYURIDINE
HEAVY WATER
KETONES
LACTOBACILLUS
SUBSTRATES
ANTIMETABOLITES
AZINES
BACTERIA
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
DRUGS
ENZYMES
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
MICROORGANISMS
NUCLEIC ACID REPLICATION
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PYRIMIDINES
URACILS
WATER
550201* - Biochemistry- Tracer Techniques