Document Detail


Mutationally altered ribonucleotide reductase from Escherichia coli: characterization of mutations isolated on multicopy plasmids.
MedLine Citation:
PMID:  6389503     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The Escherichia coli ribonucleotide reductase genes (nrd genes) were mutagenized at random. Point mutations were introduced in vitro into a recombinant nrd plasmid. Transformants were initially screened for altered tolerance toward the drug hydroxyurea and further characterized by enzymatic and immunological methods. The screening procedure could pick out defects in either of the two subunits of ribonucleotide reductase. Cells carrying the nrd plasmid pPS2 were earlier shown to have levels of ribonucleotide reductase molecules that were 10 to 20 times higher than those in wild-type cells. We now demonstrate that the enzymatic activity in gently lysed pPS2-containing cells on cellophane disks is six times higher than in wild-type cells. Supplementation of the pPS2-containing lysates with a purified thioredoxin system results in a further 4.5-fold stimulation of the enzymatic activity, which implies a functional shortage of the electron donor system(s) for ribonucleotide reduction in pPS2-containing cells.
Authors:
A Platz; B M Sjöberg
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of bacteriology     Volume:  160     ISSN:  0021-9193     ISO Abbreviation:  J. Bacteriol.     Publication Date:  1984 Dec 
Date Detail:
Created Date:  1985-01-18     Completed Date:  1985-01-18     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2985120R     Medline TA:  J Bacteriol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1010-6     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Cloning, Molecular
Drug Resistance, Microbial
Escherichia coli / drug effects,  enzymology,  genetics*
Genes*
Genes, Bacterial*
Hydroxyurea / pharmacology
Kinetics
Mutation*
Phenotype
Plasmids*
Ribonucleotide Reductases / genetics*,  metabolism
Transformation, Bacterial
Chemical
Reg. No./Substance:
127-07-1/Hydroxyurea; EC 1.17.4.-/Ribonucleotide Reductases
Comments/Corrections

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