scholarly journals ISOLATION AND CHARACTERIZATION OF AMBER SUPPRESSORS IN YEAST

Genetics ◽  
1976 ◽  
Vol 82 (2) ◽  
pp. 251-272
Author(s):  
Susan W Liebman ◽  
Fred Sherman ◽  
John W Stewart
Keyword(s):  
Amino Acids ◽  
Cytochrome C ◽  
Yeast Strain ◽  
Normal Amount ◽  
Amber Mutation ◽  
Genetic Analyses ◽  
Isolation And Characterization ◽  
And Function ◽  
Nonsense Suppressors

ABSTRACT Nonsense suppressors were obtained in a haploid yeast strain containing eight nutritional mutations, that are assumed to be amber or ochre, and the cyc1-179 amber mutation that has a UAG codon corresponding to position 9 in iso-1-cytochrome c. Previous studies established that the biosynthesis and function of iso-1-cytochrome c is compatible with replacements at position 9 of amino acids having widely different structures (Stewart and Sherman 1972). UV-induced revertants, selected on media requiring the reversion of one or two of the amber nutritional markers, were presumed to contain a suppressor if there was the unselected reversion of at least one other marker. The 1088 suppressors that were isolated could be divided into 78 phenotypic classes. Only 43 suppressors of three classes caused the production of more than 50% of the normal amount of iso-1-cytochrome c in the cyc1-179 strain. Genetic analyses indicated that all of these highly efficient amber suppressors are allelic to one or another of the eight suppressors which cause the insertion of tyrosine at ochre (UAA) codons (Gilmore, Stewart and Sherman 1971). Furthermore, only tyrosine has been identified at position 9 in iso-1-cytochrome cin cyc1-179 strains suppressed with these efficient amber suppressors.

scholarly journals Isolation and characterization of the cDNAs encoding two isoforms of subunit CIX of bovine cytochrome c oxidase.

1990 ◽  
Vol 265 (5) ◽  
pp. 2677-2681
Author(s):  
R Lightowlers ◽  
G Ewart ◽  
R Aggeler ◽  
Y Z Zhang ◽  
L Calavetta ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Isolation And Characterization

scholarly journals Conservation of dishevelled structure and function between flies and mice: isolation and characterization of Dvl2

1996 ◽  
Vol 58 (1-2) ◽  
pp. 15-26 ◽  
Author(s):  
J. Klingensmith ◽  
Y. Yang ◽  
J.D. Axelrod ◽  
D.R. Beier ◽  
N. Perrimon ◽  
...  
Keyword(s):  
Structure And Function ◽  
Isolation And Characterization ◽  
And Function

scholarly journals Isolation and Characterization of Mutations in theEscherichia coli Regulatory Protein XapR

1999 ◽  
Vol 181 (14) ◽  
pp. 4397-4403 ◽  
Author(s):  
Casper Jørgensen ◽  
Gert Dandanell
Keyword(s):  
Amino Acids ◽  
Purine Nucleoside Phosphorylase ◽  
Mutational Analysis ◽  
Regulatory Protein ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Wild Type ◽  
Isolation And Characterization ◽  
In The Wild

ABSTRACT In this work, the LysR-type protein XapR has been subjected to a mutational analysis. XapR regulates the expression of xanthosine phosphorylase (XapA), a purine nucleoside phosphorylase inEscherichia coli. In the wild type, full expression of XapA requires both a functional XapR protein and the inducer xanthosine. Here we show that deoxyinosine can also function as an inducer in the wild type, although not to the same extent as xanthosine. We have isolated and characterized in detail the mutants that can be induced by other nucleosides as well as xanthosine. Sequencing of the mutants has revealed that two regions in XapR are important for correct interactions between the inducer and XapR. One region is defined by amino acids 104 and 132, and the other region, containing most of the isolated mutations, is found between amino acids 203 and 210. These regions, when modelled into the three-dimensional structure of CysB from Klebsiella aerogenes, are placed close together and are most probably directly involved in binding the inducer xanthosine.

ISOLATION AND CHARACTERIZATION OF RIBONUCLEIC ACID FROM RAT LENS

1962 ◽  
Vol 40 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Anima Devi
Keyword(s):  
Amino Acids ◽  
The Other ◽  
Ocular Lens ◽  
E Coli ◽  
Isolation And Characterization ◽  
Coiled Structure ◽  
Calf Thymus ◽  
Original Procedure ◽  
Polynucleotide Chain

RNA from rat ocular lens has been isolated by a method based on Kirby's original procedure (7), but greatly modified so as to avoid any degradation of RNA by RNase during the process of its extraction from lenses. The absorption at 260 mμ of a 1.0% solution of this purified material in a 1-cm cell is 1.95. Its N/P ratio is 1.58. It has 20 to 25% activity of that of yeast-soluble RNA in accepting activated amino acids. When this RNA (like all other RNA's) is heated and cooled the polynucleotide chain can again form loops, thus suggesting a randomly coiled structure for this RNA. On the other hand, DNA preparations from calf thymus, rat liver, and E. coli showed irreversible changes when heated and cooled.

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