Linked Life Data

7024267

Source:http://linkedlifedata.com/resource/pubmed/id/7024267

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
1981-11-22
pubmed:abstractText
Ribonucleotide reductase is responsible for the reduction of the 2'-hydroxy moiety of all four ribonucleoside diphosphates to the corresponding deoxyribonucleotides. The overall activity of the enzyme is regulated by the allosteric effectors ATP (activator) and dATP (inhibitor), and the enzyme's substrate specificity is also controlled by nucleotide effectors. For instance, wild type ribonucleotide reductase from mouse T-lymphoma (S49) cells requires dGTP as a positive effector for ADP reduction. This effect of dGTP causes a reciprocal inhibition of CDP reduction. The dGuo-L mutant cell line, resistant to growth inhibition by exogenous deoxyguanosine, contains a nucleotide-binding subunit, protein M1, that conveys to its CDP reductase an insensitivity to dGTP (and dTTP) inhibition. The dGuo-L protein M1 also shows a decreased capacity to use ADP as a substrate, and therefore, the regulation of the substrate specificity is altered in the mutant protein M1. Another mutant cell line, dGuo-200-1, is resistant to deoxyadenosine and its ribonucleotide reductase is abnormally resistant to inhibition by dATP. The isolated mutant protein M1 from dGuo-200-1 cells has a CDP reductase activity which is stimulated by dATP, unlike the wild type enzyme which is inhibited by dATP. It appears that this mutant enzyme has lost the capacity to distinguish between dATP and ATP, but is still sensitive to regulation by dGTP and dTTP. Thus, the site of protein M1 regulating overall activity is altered in the dGuo-200-1 mutant, while the site regulating substrate specificity is normal. These characteristics of the mutants provide genetic evidence for two independent allosteric domains of protein M1, each responsible for a different aspect of nucleotide sensitivity of ribonucleotide reductase.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
256
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10193-7
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1981
pubmed:articleTitle
Evidence for genetically independent allosteric regulatory domains of the protein M1 subunit of mouse ribonucleotide reductase.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't