An efficient prebiotic synthesis of cytosine and uracil
Article Abstract:
A prebiotic synthesis mechanism for the formation of the pyrimidines, cytosine and uracil, is given. The reaction of cyanoacetaldehyde with urea forms these pyrimidines, but the yield is low if the concentration of the urea is low. If the urea solution is concentrated, 30% to 50% of cytosine is formed and the hydrolysis of cytosine forms uracil. This shows that since, on the early Earth concentrated urea solutions were present in drying lagoons and pools, the pyrimidine bases required in the RNA world were probably formed by this mechanism.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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How to make a nucelotide
Article Abstract:
Unrau and Bartel have described the isolation of RNA molecules that are able to catalyze the synthesis of the nucleotide 4-thiouridine from 4-thiouracil and activated ribose. The ribozyme evolves to form the glycosidic bond to join a sugar to a base, to produce a nucleotide. The discovery fills an important gape in a generalized scheme for the evolution of the RNA world.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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Nucleosome mobilization catalyzed by the yeast SWI/SNF complex
Article Abstract:
A model system was used to show that the yeast SWI/SNF complex can place nucleosomes in an ATP-dependent reaction favouring the attachment of a histone octamer to an acceptor site on the same DNA molecule. SWI/SNF-mediated displacement is blocked by a barrie in the DNA, indicating that the repositioning involves sliding or tracking of nucleosomes along DNA.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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