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Oligomerization sta...
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Rofougaran, RezaUmeå universitet,Institutionen för medicinsk kemi och biofysik,Department of Medical Biochemistry and Biophysics; Umeå University
(författare)
Oligomerization status directs overall activity regulation of the Escherichia coli class Ia ribonucleotide reductase
- Artikel/kapitelEngelska2008
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American Society for Biochemistry and Molecular Biology,2008
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Nummerbeteckningar
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LIBRIS-ID:oai:DiVA.org:umu-10704
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https://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-10704URI
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https://doi.org/10.1074/jbc.M806738200DOI
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https://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-45734URI
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Språk:engelska
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Sammanfattning på:engelska
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Ribonucleotide reductase (RNR) is a key enzyme for the synthesis of the four DNA building blocks. Class Ia RNRs contain two subunits, denoted R1 (α) and R2 (β). These enzymes are regulated via two nucleotide-binding allosteric sites on the R1 subunit, termed the specificity and overall activity sites. The specificity site binds ATP, dATP, dTTP, or dGTP and determines the substrate to be reduced, whereas the overall activity site binds dATP (inhibitor) or ATP. By using gas-phase electrophoretic mobility macromolecule analysis and enzyme assays, we found that the Escherichia coli class Ia RNR formed an inhibited α4β4 complex in the presence of dATP and an active α2β2 complex in the presence of ATP (main substrate: CDP), dTTP (substrate: GDP) or dGTP (substrate: ADP). The R1-R2 interaction was 30–50 times stronger in the α4β4 complex than in the α2β2complex, which was in equilibrium with free α2 and β2 subunits. Studies of a known E. coli R1 mutant (H59A) showed that deficient dATP inhibition correlated with reduced ability to form α4β4 complexes. ATP could also induce the formation of a generally inhibited α4β4 complex in the E. coli RNR but only when used in combination with high concentrations of the specificity site effectors, dTTP/dGTP. Both allosteric sites are therefore important for α4β4 formation and overall activity regulation. The E. coli RNR differs from the mammalian enzyme, which is stimulated by ATP also in combination with dGTP/dTTP and forms active and inactive α6β2 complexes.
Ämnesord och genrebeteckningar
Biuppslag (personer, institutioner, konferenser, titlar ...)
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Crona, MikaelStockholms universitet,Umeå universitet,Institutionen för molekylärbiologi (Medicinska fakulteten),Institutionen för molekylärbiologi och funktionsgenomik,Britt-Marie Sjöberg
(författare)
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Vodnala, Munender,1977-Umeå universitet,Institutionen för medicinsk kemi och biofysik,Department of Medical Biochemistry and Biophysics, Umeå University(Swepub:umu)murvoa04
(författare)
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Sjöberg, Britt-MarieStockholms universitet,Umeå universitet,Institutionen för molekylärbiologi (Medicinska fakulteten),Institutionen för molekylärbiologi och funktionsgenomik(Swepub:su)bsjob
(författare)
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Hofer, AndersUmeå universitet,Institutionen för medicinsk kemi och biofysik,Department of Medical Biochemistry and Biophysics, Umeå University(Swepub:umu)anho0002
(författare)
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Umeå universitetInstitutionen för medicinsk kemi och biofysik
(creator_code:org_t)
Sammanhörande titlar
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Ingår i:Journal of Biological Chemistry: American Society for Biochemistry and Molecular Biology283:51, s. 35310-353180021-92581083-351X
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