Recharacterization of fungal dinucleoside polyphosphate (HS3)

McNaughton, David R.; Klassen, Glen R.; Loewen, Peter C.; LéJohn, Herb B.

doi:10.1139/o78-036

Cited by 4 publications

(1 citation statement)

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“…Recently, LeJohn and his associates (5,6) reported that several species of higher and lower fungi including Achlyu sp. and Blastocladielltr emersonii synthesize, during vegetative growth, large amounts of two highly phosphorylated UV-absorbing compounds which they described as "hot spots" (HS-3 and HS-2).…”

Section: Discussionmentioning

confidence: 99%

The diguanosine nucleotides: do they exist in aquatic fungi?

Warner¹,

Thomas²,

Shridhar³

et al. 1977

Can. J. Biochem.

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The aquatic fungi Achlya ambisexualis and Blastocladiella emersonii were grown in the presence of 32Pi and the 32P-labeled acid-soluble nucleotide fractions were analyzed by ion-exchange chromatography on DEAE-cellulose. Selected column fractions containing diguanosine tri- and tetra-phosphates (Gp3G and Gp4G) added as chromatographic markers were analyzed further for 32P by chromatography and (or) enzyme hydrolysis. The results of these experiments clearly indicate that neither Gp4G nor Gp3G is synthesized during vegetative growth of these organisms and cast doubt on the hypothesis that diguanosine nucleotides are important metabolic regulators in fungi.

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Section: Discussionmentioning

confidence: 99%

The diguanosine nucleotides: do they exist in aquatic fungi?

Warner¹,

Thomas²,

Shridhar³

et al. 1977

Can. J. Biochem.

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Determination of the role of polyphosphate in transport-coupled phosphorylation in the yeast Saccharomyces cerevisiae

Schuddemat¹,

Cc²,

et al. 1990

Antonie van Leeuwenhoek

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The role of polyphosphate in 2-deoxy-D-glucose transport was studied in yeast cells, pulse-labeled with [32P]orthophosphate, by comparing the concentrations and specific activities of polyphosphate, orthophosphate and 2-dGlc-phosphate. When 2-dGlc transport was measured under aerobic conditions, it appeared that polyphosphate replenished the orthophosphate pool, indicating that polyphosphate has, at least mainly, an indirect role in sugar phosphorylation. Also in cells with a reduced respiratory capacity, due to a treatment with antimycin A, no direct role for polyphosphate in 2-dGlc transport could be detected. Under these conditions, only a very limited breakdown of polyphosphate occurred, probably because of the small decrease in the orthophosphate concentration.

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The ribonucleotide reductases — A unique group of metalloenzymes essential for cell proliferation

Lammers

Follmann

1983

Structure and Bonding

152

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Reductive elimination of the 2'-hydroxyl group from ribonucleotides to yield 2'-deoxyribonucleotides, the monomeric precursors of DNA, requires an uncommon type of enzyme catalysis in which the transition metals, manganese, iron, or cobalt, and free radical intermediates cooperate. In the group of deoxyadenosylcobalamin (coenzyme B 12)-dependent ribonucleotide reductases the coenzyme supplies a transient radical pair of deoxyadenosyl, and cob(II)alamin whereas in the nonheme-iron group of enzymes a protein subunit carries a stable tyrosyl radical coordinated to a binuclear iron(III) complex; the manganese-dependent enzymes are less precisely known. The radicals are thought to function in hydrogen transfer from cysteine SH to the ribonucleotide substrate, and the metal complexes are apparently needed to generate and stabilize the radicals. In aerobic organisms oxygen also plays a critical role in these processes and hence in DNA synthesis and cell proliferation. In addition to the transition metals, Mg 2+ or Ca 2+ are required by several ribonucleotide reductases for structural integrity. However the most potent inhibitors of deoxyribonucleotide biosynthesis (of potential interest in chemotherapy) are not metal chelators but radical scavengers. Cell cycle arrest and cell death produced by simple chemicals like N-hydroxyurea and hydroxamates can be traced back to their reaction with ribonucleotide reductase. Evidence is accumulating that independent enzymes of deoxyribonucleotide and DNA synthesis are functionally coupled in a novel type of supramolecular structure.

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Recharacterization of fungal dinucleoside polyphosphate (HS3)

Cited by 4 publications

References 0 publications

The diguanosine nucleotides: do they exist in aquatic fungi?

The diguanosine nucleotides: do they exist in aquatic fungi?

Determination of the role of polyphosphate in transport-coupled phosphorylation in the yeast Saccharomyces cerevisiae

The ribonucleotide reductases — A unique group of metalloenzymes essential for cell proliferation

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