scholarly journals Selection and characterization of ricin toxin A-chain mutations in Saccharomyces cerevisiae.

1989 ◽  
Vol 9 (2) ◽  
pp. 415-420 ◽  
Author(s):  
A Frankel ◽  
D Schlossman ◽  
P Welsh ◽  
A Hertler ◽  
D Withers ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ricinus Communis ◽  
Single Amino Acid ◽  
Toxin A ◽  
Reactive Material ◽  
Ricin Toxin ◽  
Gal1 Promoter ◽  
Active Site Cleft ◽  
A Chain

A DNA sequence encoding the A chain of ricin toxin (RTA) from the castor bean plant, Ricinus communis, was placed under GAL1 promoter control and transformed into Saccharomyces cerevisiae. Induction of expression of RTA was lethal. This lethality was the basis for a selection of mutations in RTA which inactivated the toxin. A number of mutant alleles which encoded cross-reactive material were sequenced. Eight of the first nine mutant RTAs studied showed single-amino-acid changes involving residues located in the proposed active-site cleft.

Selection and characterization of ricin toxin A-chain mutations in Saccharomyces cerevisiae

1989 ◽  
Vol 9 (2) ◽  
pp. 415-420
Author(s):  
A Frankel ◽  
D Schlossman ◽  
P Welsh ◽  
A Hertler ◽  
D Withers ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ricinus Communis ◽  
Single Amino Acid ◽  
Toxin A ◽  
Reactive Material ◽  
Ricin Toxin ◽  
Gal1 Promoter ◽  
Active Site Cleft ◽  
A Chain

A DNA sequence encoding the A chain of ricin toxin (RTA) from the castor bean plant, Ricinus communis, was placed under GAL1 promoter control and transformed into Saccharomyces cerevisiae. Induction of expression of RTA was lethal. This lethality was the basis for a selection of mutations in RTA which inactivated the toxin. A number of mutant alleles which encoded cross-reactive material were sequenced. Eight of the first nine mutant RTAs studied showed single-amino-acid changes involving residues located in the proposed active-site cleft.

scholarly journals Inducible cell ablation in Drosophila by cold-sensitive ricin A chain

Development ◽  
1992 ◽  
Vol 114 (3) ◽  
pp. 681-687 ◽  
Author(s):  
K.G. Moffat ◽  
J.H. Gould ◽  
H.K. Smith ◽  
C.J. O'Kane
Keyword(s):  
Single Amino Acid ◽  
Temperature Sensitive ◽  
Temperature Dependent ◽  
Ricin Toxin ◽  
Cell Ablation ◽  
Active Site Cleft ◽  
Cold Sensitive ◽  
Low Toxicity ◽  
A Chain ◽  
Ricin A

We have developed a system for temperature-inducible killing of specific cells in the fruitfly Drosophila melanogaster. The system overcomes many of the limitations of existing cell ablation methods and is in principle applicable to any non-homeothermic eukaryote. Temperature-sensitive and cold-sensitive mutations in the ricin toxin A chain (RTA) of castor bean were generated in yeast. One cold-sensitive mutation, RAcs2, produced temperature-dependent ablation of eye cells in Drosophila when expressed under control of the eye-specific sev enhancer. At 29 degrees C, cell death was observed within 7 hours in the developing eye and no obvious toxic effects were observed elsewhere; at 18 degrees C, extremely low toxicity was observed. DNA sequencing of RAcs2 revealed a single amino acid substitution in the RTA active site cleft.

Identification of a Functional Domain Within the Essential Core of Histone H3 That Is Required for Telomeric and HM Silencing in Saccharomyces cerevisiae

Genetics ◽  
2003 ◽  
Vol 163 (1) ◽  
pp. 447-452 ◽  
Author(s):  
Jeffrey S Thompson ◽  
Marilyn L Snow ◽  
Summer Giles ◽  
Leslie E McPherson ◽  
Michael Grunstein
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Amino Acid Substitution ◽  
Histone H3 ◽  
Single Amino Acid ◽  
Functional Domain ◽  
Partial Loss ◽  
Histone Fold ◽  
Gal1 Promoter ◽  
Substitution Mutations

Abstract Fourteen novel single-amino-acid substitution mutations in histone H3 that disrupt telomeric silencing in Saccharomyces cerevisiae were identified, 10 of which are clustered within the α1 helix and L1 loop of the essential histone fold. Several of these mutations cause derepression of silent mating locus HML, and an additional subset cause partial loss of basal repression at the GAL1 promoter. Our results identify a new domain within the essential core of histone H3 that is required for heterochromatin-mediated silencing.

scholarly journals Delivery of Ricin Toxin A-Chain by Peptide-Targeted Mesoporous Silica Nanoparticle-Supported Lipid Bilayers

2012 ◽  
Vol 1 (3) ◽  
pp. 348-353 ◽  
Author(s):  
Katharine Epler ◽  
David Padilla ◽  
Genevieve Phillips ◽  
Peter Crowder ◽  
Robert Castillo ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Lipid Bilayers ◽  
Silica Nanoparticle ◽  
Supported Lipid Bilayers ◽  
Toxin A ◽  
Mesoporous Silica Nanoparticle ◽  
Ricin Toxin ◽  
A Chain

Role of arginine 180 and glutamic acid 177 of ricin toxin A chain in enzymatic inactivation of ribosomes

1990 ◽  
Vol 10 (12) ◽  
pp. 6257-6263
Author(s):  
A Frankel ◽  
P Welsh ◽  
J Richardson ◽  
J D Robertus
Keyword(s):  
Enzyme Activity ◽  
Glutamic Acid ◽  
Structural Information ◽  
Wild Type ◽  
Toxin A ◽  
Mutant Proteins ◽  
Ricin Toxin ◽  
Enzymatic Inactivation ◽  
A Chain

The gene for ricin toxin A chain was modified by site-specific mutagenesis to change arginine 180 to alanine, glutamine, methionine, lysine, or histidine. Separately, glutamic acid 177 was changed to alanine and glutamic acid 208 was changed to aspartic acid. Both the wild-type and mutant proteins were expressed in Escherichia coli and, when soluble, purified and tested quantitatively for enzyme activity. A positive charge at position 180 was found necessary for solubility of the protein and for enzyme activity. Similarly, a negative charge with a proper geometry in the vicinity of position 177 was critical for ricin toxin A chain catalysis. When glutamic acid 177 was converted to alanine, nearby glutamic acid 208 could largely substitute for it. This observation provided valuable structural information concerning the nature of second-site mutations.

Detection of an abasic site in RNA with stem-loop DNA beacons: Application to an activity assay for Ricin Toxin A-Chain

2008 ◽  
Vol 70 (6) ◽  
pp. 945-953 ◽  
Author(s):  
Setu Roday ◽  
Matthew B. Sturm ◽  
Dukagjin M. Blakaj ◽  
Vern L. Schramm
Keyword(s):  
Abasic Site ◽  
Activity Assay ◽  
Toxin A ◽  
Stem Loop ◽  
Ricin Toxin ◽  
A Chain
Sign in / Sign up

Export Citation Format

Share Document