Change search
ReferencesLink to record
Permanent link

Direct link
Mutant R1 proteins from Escherichia coli class Ia ribonucleotide reductase with altered responses to dATP inhibition.
Stockholm University, Faculty of Science, Department of Molecular Biology and Functional Genomics.
Stockholm University, Faculty of Science, Department of Molecular Biology and Functional Genomics.
Stockholm University, Faculty of Science, Department of Molecular Biology and Functional Genomics.
2004 (English)In: J Biol Chem, ISSN 0021-9258, Vol. 279, no 15, 14496-501 p.Article in journal (Other academic) Published
Abstract [en]

Aerobic ribonucleotide reductase from Escherichia coli regulates its level of activity by binding of effectors to an allosteric site in R1, located to the proposed interaction area of the two proteins that comprise the class I enzyme. Activity is increased by ATP binding and decreased by dATP binding. To study the mechanism governing this regulation, we have constructed three R1 proteins with mutations at His-59 in the activity site and one R1 protein with a mutation at His-88 close to the activity site and compared their allosteric behavior to that of the wild type R1 protein. All mutant proteins retained about 70% of wild type enzymatic activity. We found that if residue His-59 was replaced with alanine or asparagine, the enzyme lost its normal response to the inhibitory effect of dATP, whereas the enzyme with a glutamine still managed to elicit a normal response. We saw a similar result if residue His-88, which is proposed to hydrogen-bond to His-59, was replaced with alanine. Nucleotide binding experiments ruled out the possibility that the effect is due to an inability of the mutant proteins to bind effector since little difference in binding constants was observed for wild type and mutant proteins. Instead, the interaction between proteins R1 and R2 was perturbed in the mutant proteins. We propose that His-59 is important in the allosteric effect triggered by dATP binding, that the conserved hydrogen bond between His-59 and His-88 is important for the communication of the allosteric effect, and that this effect is exerted on the R1/R2 interaction.

Place, publisher, year, edition, pages
2004. Vol. 279, no 15, 14496-501 p.
Keyword [en]
Adenosine Triphosphate/chemistry/*metabolism, Allosteric Site, Asparagine/chemistry, Binding Sites, Cell Division, Dose-Response Relationship; Drug, Escherichia coli/*genetics/metabolism, Glutamine/chemistry, Histidine/chemistry, Hydrogen Bonding, Kinetics, Magnesium/chemistry, Models; Molecular, Mutagenesis; Site-Directed, Mutation, Oligonucleotides/chemistry, Plasmids/metabolism, Protein Binding, Ribonucleotide Reductases/chemistry/*genetics, Substrate Specificity, Surface Plasmon Resonance
URN: urn:nbn:se:su:diva-20347PubMedID: 14752109OAI: diva2:186873
Available from: 2007-03-10 Created: 2007-03-10 Last updated: 2011-01-12Bibliographically approved

Open Access in DiVA

No full text

Other links


Search in DiVA

By author/editor
Kasrayan, AlexSjöberg, Britt-Marie
By organisation
Department of Molecular Biology and Functional Genomics

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 16 hits
ReferencesLink to record
Permanent link

Direct link