scholarly journals The pseudouridine contents of the ribosomal ribonucleic acids of three vertebrate species. Numerical correspondence between pseudouridine residues and 2′-O-methyl groups is not always conserved

1978 ◽  
Vol 171 (3) ◽  
pp. 781-786 ◽  
Author(s):  
D G Hughes ◽  
B E H Maden
Keyword(s):  
Molecular Weight ◽  
Xenopus Laevis ◽  
High Molecular Weight ◽  
Hela Cells ◽  
Numerical Data ◽  
Methyl Groups ◽  
Kidney Cells ◽  
Vertebrate Species ◽  
Ribonucleic Acids ◽  
Rrna Species

The pseudouridine contents of the rRNA species of HeLa cells, mouse L-cells and Xenopus laevis cultured kidney cells were examined. Pseudouridine, like 2′-O-methylation, was found to occur relatively frequently in each of the high-molecular-weight rRNA species. However, the numerical data do not support the idea that there is a general one-to-one relationship between pseudoridine residues and 2′-O-methyl groups in vertebrate rRNA.

scholarly journals Extensive homologies between the methylated nucleotide sequences in several vertebrate ribosomal ribonucleic acids

1978 ◽  
Vol 169 (3) ◽  
pp. 531-542 ◽  
Author(s):  
M S N Khan ◽  
M Salim ◽  
B E H. Maden
Keyword(s):  
Xenopus Laevis ◽  
18S Rrna ◽  
Cultured Cells ◽  
Nucleotide Sequences ◽  
Methyl Groups ◽  
28S Rrna ◽  
Chick Embryo Fibroblast ◽  
Ribonucleic Acids ◽  
Rrna Species ◽  
Complete Digestion

The methylated nucleotide sequences in the rRNA molecules of the following vertebrate cultured cells were compared: human (HeLa); hamster (BHK/C13); mouse (L); chick-embryo fibroblast; Xenopus laevis kidney. In each species the combined 18S, 28S and 5.8S molecules possess approx. 110-115 methyl groups, and the methylated oligonucleotides released after complete digestion of the rRNA by T1 ribonuclease encompass several hundred nucleotides. “Fingerprints” of the three mammalian methyl-labelled 18S rRNA species were qualitatively indistinguishable. “Fingerprints” of digests of 28S rRNA of hamster and mouse L-cells were extremely similar to those of HeLa cells, differing in one and three methylated oligonucleotides respectively. “Fingerprints” of methyl-labelled rRNA from chick and Xenopus strongly resembled those of mammals in most respects, but differed in several oligonucleotides in both 18S and 28S rRNA. At least some of the differences between “fingerprints” appear to be due to single base changes or to the presence or absence of methyl groups at particular points in the primary sequence. The findings strongly suggest that the methylated-nucleotide sequences are at least 95% homologous between the rRNA molecules of the two most distantly related vertebrates compared, man and Xenopus laevis.

scholarly journals Stereospecific Isotopic Labeling of Methyl Groups for NMR Spectroscopic Studies of High-Molecular-Weight Proteins

2010 ◽  
Vol 49 (11) ◽  
pp. 1958-1962 ◽  
Author(s):  
Pierre Gans ◽  
Olivier Hamelin ◽  
Remy Sounier ◽  
Isabel Ayala ◽  
M. Asunción Durá ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Isotopic Labeling ◽  
Spectroscopic Studies ◽  
Methyl Groups ◽  
High Molecular Weight Proteins

scholarly journals The crystalline yolk-platelet proteins and their soluble plasma precursor in an amphibian, Xenopus laevis

1971 ◽  
Vol 124 (4) ◽  
pp. 759-766 ◽  
Author(s):  
M. R. Redshaw ◽  
B. K. Follett
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Xenopus Laevis ◽  
Amino Acid Composition ◽  
High Molecular Weight ◽  
Molecular Rearrangement ◽  
Yolk Proteins ◽  
Platelet Protein ◽  
Yolk Platelet ◽  
Preparative Ultracentrifugation

A single lipophosphoprotein complex, vitellogenin, was isolated and purified from the plasma of oestrogen-stimulated female toads by preparative ultracentrifugation and chromatography on TEAE-cellulose (triethylaminoethylcellulose). The protein contains 12% lipid, 1.5% phosphorus, 1.6% calcium and smaller amounts of carbohydrates and biliverdin. In amino acid composition it is identical with total yolk-platelet protein. The platelet protein, however, is fractionated on TEAE-cellulose into two components, a high-molecular-weight lipovitellin and a smaller phosvitin. Analyses of the soluble plasma vitellogenin suggest that it is a complex of two phosvitin molecules covalently bound to one lipovitellin dimer, and that it is the immediate precursor of the yolk proteins, into which it is converted by a molecular rearrangement. Uptake of vitellogenin from the plasma into the growing oocyte, and its subsequent crystallization as a yolk platelet, appear to be enhanced by gonadotrophic hormones.

Sequence-Specific Assignments of Methyl Groups in High-Molecular Weight Proteins

2004 ◽  
Vol 126 (12) ◽  
pp. 3710-3711 ◽  
Author(s):  
Daiwen Yang ◽  
Yu Zheng ◽  
Dingjiang Liu ◽  
Daniel F. Wyss
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Methyl Groups ◽  
High Molecular Weight Proteins

scholarly journals Microinjection of ubiquitin: intracellular distribution and metabolism in HeLa cells maintained under normal physiological conditions.

1987 ◽  
Vol 104 (3) ◽  
pp. 537-546 ◽  
Author(s):  
N Carlson ◽  
M Rechsteiner
Keyword(s):  
Molecular Weight ◽  
Protein Synthesis ◽  
Size Distribution ◽  
High Molecular Weight ◽  
Hela Cells ◽  
Insoluble Fraction ◽  
Nuclear Fraction ◽  
Molecular Weights ◽  
Differential Sedimentation ◽  
Triton X

Radioiodinated ubiquitin was introduced into HeLa cells by erythrocyte-mediated microinjection. Subsequent electrophoretic analyses revealed that the injected ubiquitin molecules were rapidly conjugated to HeLa proteins. At equilibrium, 10% of the injected ubiquitin was conjugated to histones and 40% was distributed among conjugates of higher molecular weight. Although the remaining ubiquitin molecules appeared to be unconjugated, the free pool of ubiquitin decreased by one-third and additional conjugates were present when electrophoresis was performed at low temperature under nonreducing conditions. Molecular weights of these labile conjugates suggest that they are ubiquitin adducts in thiolester linkage to activating enzymes. Despite the fairly rapid degradation of injected ubiquitin (t1/2 approximately 10-20 h), the size distribution of ubiquitin conjugates within interphase HeLa cells remained constant for at least 24 h after injection. The intracellular locations of ubiquitin and ubiquitin conjugates were determined by autoradiography, by differential sedimentation of subcellular fractions in sucrose, and by extraction of injected cells with buffer containing Triton X-100. Free ubiquitin was found mostly in the cytosolic or Triton X-100-soluble fractions. As expected, histone conjugates were located predominately in the nuclear fraction and exclusively in the Triton X-100-insoluble fraction. Although high molecular weight conjugates were enriched in the Triton X-100-insoluble fraction, their size distribution was similar to that of soluble conjugates. When injected HeLa cells were exposed to cycloheximide to inhibit protein synthesis, the size distribution of ubiquitin conjugates was similar to that found in untreated cells. Moreover, high molecular weight conjugates decreased less than 20% after inhibition of protein synthesis. These results indicate that most ubiquitin conjugates are not newly synthesized proteins which have been marked for destruction.

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