1peu
Ribonucleotide Reductase Protein R1E from Salmonella typhimurium
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OverviewOverview
The three-dimensional structure of the large subunit of the first member, of a class Ib ribonucleotide reductase, R1E of Salmonella typhimurium, has, been determined in its native form and together with three allosteric, effectors. The enzyme contains the characteristic ten-stranded, alpha/beta-barrel with catalytic residues at a finger loop in its center, and with redox-active cysteine residues at two adjacent barrel strands., Structures where the redox-active cysteine residues are in reduced thiol, form and in oxidized disulfide form have been determined revealing local, structural changes. The R1E enzyme differs from the class Ia enzyme, Escherichia coli R1, by not having an overall allosteric regulation. This, is explained from the structure by differences in the N-terminal domain, which is about 50 residues shorter and lacks the overall allosteric, binding site. R1E has an allosteric substrate specificity regulation site, and the binding site for the nucleotide effectors is located at the dimer, interface similarly as for the class Ia enzymes. We have determined the, structures of R1E in the absence of effectors and with dTTP, dATP and dCTP, bound. The low affinity for ATP at the specificity site is explained by a, tyrosine, which hinders nucleotides containing a 2'-OH group to bind.
About this StructureAbout this Structure
1PEU is a Single protein structure of sequence from Salmonella typhimurium with MG and DTP as ligands. Active as Ribonucleoside-diphosphate reductase, with EC number 1.17.4.1 Full crystallographic information is available from OCA.
ReferenceReference
Structure of the large subunit of class Ib ribonucleotide reductase from Salmonella typhimurium and its complexes with allosteric effectors., Uppsten M, Farnegardh M, Jordan A, Eliasson R, Eklund H, Uhlin U, J Mol Biol. 2003 Jun 27;330(1):87-97. PMID:12818204
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