α-Hydroxy-β,β-dimethyl-γ-butyrolactone

Carter, Herbert E.; Ney, Luman F.

doi:10.1021/ja01846a502

Cited by 10 publications

(5 citation statements)

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“…A few of the most pertinent quantitative data on which this interpretation can be based are the following. Indirect determinations have given a width of 40 A for thymonucleohistone (24). In the recent precise x-ray diffraction analysis of deoxyribosenucleoprotamine Feughelman el al.…”

Section: Morphology Of Ti-ie Nucleus and Chromosomesmentioning

confidence: 99%

Electron Microscopic Observations on the Submicroscopic Morphology of the Meiotic Nucleus and Chromosomes

Robertis

1956

The Journal of Cell Biology

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Since the discovery of the chromosomes and their behavior in mitosis and meiosis, cytologists and cytogeneticists have been largely preoccupied with the nucleus rather than the cytoplasm and have devoted much attention to the problems of reduplication of chromosomes, mutation, and the linear array and function of genes.On the other hand, investigators concerned with submicroscopic morphology worked mainly on the fine structure of cytoplasm and its organelles (1) and as yet relatively little progress has been achieved on the ultrastructural organization of the nucleus and chromosomes. There is a real need for the application of modern techniques of analytical cytology to the problems of chromosome structure in an effort to settle many points of disagreement in the cytological literature (2). Furthermore, the high resolution recently reached by means of the electron microscope on properly fixed and sectioned material offers the possibility of visualizing in situ the nucleoproteins and other macromolecular components which biochemists have been studying in vitro after isolation.From the genetic viewpoint knowledge of the fine structure of chromosomes is of particular importance because of recent evidence which tends to identify the gene with macromolecules of nucleoprotein (3, 4) and to demonstrate, at least for simple genetic systems, that the "one dimensionality and divisibility" of genetic material persist down to its ultimate molecular structure (5).Early attempts to study nuclear components with the electron microscope consisted of observations on isolated lampbrush chromosomes of amphibian ovocytes (6-8) and on nuclear fragments (9). Some workers reported the presence of fibrillar structures about 500 A in diameter (6) that under certain conditions appeared as paired strands (7). However, this has been contradicted by others who found no evidence of single or paired strands in cross-sections of *

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Section: Morphology Of Ti-ie Nucleus and Chromosomesmentioning

confidence: 99%

Electron Microscopic Observations on the Submicroscopic Morphology of the Meiotic Nucleus and Chromosomes

Robertis

1956

The Journal of Cell Biology

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“…The haft-life at 25°C and pH 8 is 50 years for pantothenic acid, but it is 2,350 years for acetyl-13-alanine. The rapid hydrolysis of the nitrile of pantoic acid was noted by Carter and Ney (1941) and is probably due to a similar internal nucleophilic attack by the ~/-hydroxyl. The hydrolysis of pantothenic acid is not fast enough to be a disadvantage in a living organism, but it could have been important on the primitive Earth.…”

Section: Discussionmentioning

confidence: 59%

Prebiotic syntheses of vitamin coenzymes: II. Pantoic acid, pantothenic acid, and the composition of coenzyme A

Miller

Schlesinger

1993

J Mol Evol

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Pantoic acid can by synthesized in good prebiotic yield from isobutyraldehyde or et-ketoisovaleric acid + H2CO + HCN. Isobutyraldehyde is the Strecker precursor to valine and a-ketoisovaleric acid is the valine transamination product. Mg z+ and Ca 2+ as well as several transition metals are catalysts for the a-ketoisovaleric acid reaction. Pantothenic acid is produced from pantoyl lactone (easily formed from pantoic acid) and the relatively high concentrations of I~-alanine that would be formed on drying prebiotic amino acid mixtures. There is no selectivity for this reaction over glycine, alanine, or ~/-amino butyric acid. The components of coenzyme A are discussed in terms of ease of prebiotic formation and stability and are shown to be plausible choices, but many other compounds are possible. The ~/-OH of pantoic acid needs to be capped to prevent decomposition of pantothenic acid. These results suggest that coenzyme A function was important in the earliest metabolic pathways and that the coenzyme A precursor contained most of the components of the present coenzyme.

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“…Several methods have been reported for the preparation of β-methylcysteine derivatives, including displacement of an O -tosylated threonine derivative with potassium thioacetate, 8 conjugate addition of a thiol to an oxazolone derivative of an α,β-dehydroamino acid to yield an S -benzyl-β-alkylcysteine upon hydrolysis 9 and acid hydrolysis of a threonine-derived thiazolidine. 10 However, while the first method gave a single stereoisomeric β-methylcysteine derivative, the latter two methods required laborious separations to access the individual diastereoisomers.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of pdCpAs and transfer RNAs activated with thiothreonine and derivatives

Chen

Fahmi

Nangreave

et al. 2012

Bioorganic & Medicinal Chemistry

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N,S-diprotected L-thiothreonine and L-allo-thiothreonine derivatives were synthesized using a novel chemical strategy, and used for esterification of the dinucleotide pdCpA. The aminoacylated dinucleotides were then employed for the preparation of activated suppressor tRNACUA transcripts. Thiothreonine and allo-thiothreonine were incorporated into a predetermined position of a catalytically competent dihydrofolate reductase (DHFR) analogue lacking cysteine, and the elaborated proteins were derivatized site-specifically at the thiothreonine residue with a fluorophore.

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α-Hydroxy-β,β-dimethyl-γ-butyrolactone

Cited by 10 publications

References 0 publications

Electron Microscopic Observations on the Submicroscopic Morphology of the Meiotic Nucleus and Chromosomes

Electron Microscopic Observations on the Submicroscopic Morphology of the Meiotic Nucleus and Chromosomes

Prebiotic syntheses of vitamin coenzymes: II. Pantoic acid, pantothenic acid, and the composition of coenzyme A

Synthesis of pdCpAs and transfer RNAs activated with thiothreonine and derivatives

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