In this paper,the molecular geometry for three tautomers of uracil and four tautomers of cytosine has been analyzed. vibrational IR spectra of the tautomers were   investigated at HF and B3LYP level using the AB initio 6-31G* and LANL2DZ basis sets from the program package Gaussian 98 (A.7 Public Domain version). The physico-chemical and biochemical properties of uracil and cytosine are one of...

in this paper,the molecular geometry for three tautomers of uracil and four tautomers of cytosine has been analyzed. vibrational ir spectra of the tautomers were   investigated at hf and b3lyp level using the ab initio 6-31g* and lanl2dz basis sets from the program package gaussian 98 (a.7 public domain version). the physico-chemical and biochemical properties of uracil and cytosine are one of...

Syntheses of cytosine, uracil, and thymine starting from interstellar molecules were examined theoretically. Potential energy surfaces for the formation protonated cytosine (CyH+), uracil (UrH+), (ThH+) cyanoacetylene (HC3N), isocyanic acid (H2NCO+), one NH3, H2O, CH3OH, respectively, determined by quantum chemical calculation using CBS-QB3 method. Barrierless pathways found all three reactions...

The study of the action of ferrous bicarbonate plus air on the pyrimidinesl has been continued and the chemical change in the pyrimidine ring examined in more detail. If an aqueous solution of cytosine is treated with the system ferrous sulfate plus sodium bicarbonate plus air, hydrolysis of the amino group occurs with the formation of uracil and the liberation of ammonia. Since uracil is forme...

In Neisseria meningitidis, uridine, deoxyuridine, cytosine, cytidine, or deoxycytidine could not be used by uracil-requiring mutants as pyrimidine sources. Consistent with these findings, only 5-fluorouracil of the different fluoropyrimidine bases and nucleosides showed any inhibitory effect on the growth of four prototrophic strains of N. meningitidis. Likewise, only radioactive uracil was rea...

Cytosine glycols (5,6-dihydroxy-5,6-dihydrocytosine) are initial products of cytosine oxidation. Because these products are not stable, virtually all biological studies have focused on the stable oxidation products of cytosine, including 5-hydroxycytosine, uracil glycols and 5-hydroxyuracil. Previously, we reported that the lifetime of cytosine glycols was greatly enhanced in double-stranded DN...

X-ray photoelectron spectroscopy was used to analyze commercially available powders of thymine, uracil, cytosine, guanine, adenine, as well DNA isolated from salmon testes and RNA torula yeast. The were pressed onto a sample holder analyzed received the manufacturer. Survey spectra high-resolution O 1s, N C 1s all nucleobases are reported, including small Na contamination in cytosine. Spectra a...

The novel transformation of cytosine oxime sulfonate (C*) to uracil sulfonate (U*) proceeded by a Co(II)-assisted benzoyl peroxide reaction, eventually leading to the conversion of cytosine to uracil.

We demonstrate that a mutant of uracil DNA glycosylase (N123D:L191A) distinguishes between cytosine and methylcytosine. Uracil DNA glycosylase (UDG) efficiently removes uracil from DNA in a reaction in which the base is flipped into the enzyme's active site. Uracil is selected over cytosine by a pattern of specific hydrogen bonds, and thymine is excluded by steric clash of its 5-methyl group wi...