Bacillus subtilis deoxyuridinetriphosphatase and its bacteriophage PBS2-induced inhibitor

Journal Article · Wed Jan 01 04:00:00 EST 1975 · J. Biol. Chem.; (United States)

OSTI ID:7216570

Price, A R; Frato, J

Extracts of Bacillus subtilis contain a deoxyuridinetriphosphatase (dUTPase) activity with a molecular weight of approximately 48,000. The enzyme is maximally active at pH 8.5, being stimulated by Mg/sup 2 +/ and inhibited by EDTA. The enzyme is specific for dUTP among all the natural nucleotides tested, with an apparent K/sub m/ for dUTP of 2 ..mu..M. Bacteriophage PBS2, whose DNA contains uracil instead of thymine, induces upon infection of B. subtilis a new 83,000-dalton protein which inhibits the host's dUTPase. The inhibitor acts immediately and reversibly in vitro to inhibit dUMP production from dUTP. The inhibitor's action is maximal in dUTPase assays performed at pH 6 to 7, and is minimal at pH 9.7. The inhibitor seems to form a higher molecular weight complex with the B. subtilis dUTPase. Increasing the pH of the medium for PBS2 infection from pH 7 to pH 8.85 caused a dramatic decrease in the synthesis of phage DNA and progeny phage. The newly synthesized DNA had an altered thymine/uracil ratio, being increased from less than 0.03 to greater than 1.0. We propose that infection at high pH prevents the PBS2-induced dUTPase inhibitor from blocking the B. subtilis dUTPase activity, thereby allowing the degradation of dUTP and the synthesis of dTTP (both of which are DNA polymerase substrates), so that thymine replaces some of the uracil normally found in PBS2 DNA.

• Research Organization: Univ. of Michigan, Ann Arbor
• OSTI ID: 7216570
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 250:22; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550500* -- Metabolism
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
AZINES
BACILLUS
BACILLUS SUBTILIS
BACTERIA
BACTERIOPHAGES
CARBOXYLIC ACIDS
CHELATING AGENTS
DEOXYURIDINE
DNA
EDTA
ENZYMES
ESTERASES
HETEROCYCLIC COMPOUNDS
HYDROLASES
HYDROXY COMPOUNDS
INFECTIVITY
INHIBITION
METABOLISM
MICROORGANISMS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PARASITES
PH VALUE
PHOSPHATASES
PROTEINS
PYRIMIDINES
RIBOSIDES
URACILS
VIRUSES