1r2f
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(New page: 200px<br /><applet load="1r2f" size="450" color="white" frame="true" align="right" spinBox="true" caption="1r2f, resolution 2.1Å" /> '''RIBONUCLEOTIDE REDUCT...)
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Revision as of 23:06, 20 November 2007
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RIBONUCLEOTIDE REDUCTASE R2F PROTEIN FROM SALMONELLA TYPHIMURIUM
Overview
The first class Ib ribonucleotide reductase R2 structure, from Salmonella, typhimurium, has been determined at 2.0 A resolution. The overall, structure is similar to the Escherichia coli class Ia enzyme despite only, 23% sequence identity. The most spectacular difference is the absence of, the pleated sheet and adjacent parts present in the E. coli R2 structure;, the heart-shaped structure loses its tip. From sequence comparisons, it, appears that this feature is shared with all other class Ib enzymes and, in this respect, is more like the mammalian class Ia enzymes. Both the, oxidized and reduced iron forms have been investigated. In the ferric iron, center, both iron ions are octahedrally coordinated and bridged by one, carboxylate and one oxide ion. The ferrous form has lost the bridging, oxide ion but is bridged by two carboxylates. Accompanying the change in, redox state, helix E changes its conformation from one covering the metal, center in the oxidized form to a more open reduced form. A narrow channel, is opened which may permit easier access of oxygen to the ferrous iron, site and to efficiently generate the tyrosyl radical.
About this Structure
1R2F is a Single protein structure of sequence from Salmonella typhimurium with FE as ligand. Active as Ribonucleoside-diphosphate reductase, with EC number 1.17.4.1 Full crystallographic information is available from OCA.
Reference
Structure of Salmonella typhimurium nrdF ribonucleotide reductase in its oxidized and reduced forms., Eriksson M, Jordan A, Eklund H, Biochemistry. 1998 Sep 22;37(38):13359-69. PMID:9748343
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