1kgp
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(New page: 200px<br /><applet load="1kgp" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kgp, resolution 2.00Å" /> '''R2F from Corynebacte...)
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Revision as of 23:12, 24 November 2007
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R2F from Corynebacterium Ammoniagenes in its Mn substituted form
Overview
Ribonucleotide reductase (RNR) is the enzyme performing de novo production, of the four deoxyribonucleotides needed for DNA synthesis. All mammals as, well as some prokaryotes express the class I enzyme which is an, alpha(2)beta(2) protein. The smaller of the homodimers, denoted R2, contains a di-iron carboxylate site which, upon reaction with molecular, oxygen, generates a stable tyrosyl radical needed for catalysis. The, three-dimensional structure of the oxidized class Ib RNR R2 from, Corynebacterium ammoniagenes has been determined at 1.85 A resolution and, refined to an R-value of 15.8% (R(free) = 21.3%). In addition, structures, of both the reduced iron-containing, and manganese-substituted protein, have been solved. The C. ammoniagenes R2 has been proposed to be, manganese-dependent. The present structure provides evidence that, manganese is not oxidized by the protein, in agreement with recent, biochemical data, and that no obvious structural abnormalities are seen in, the oxidized and reduced iron-containing forms, giving further support, that the protein is indeed an iron-dependent RNR R2. The di-manganese, structure also provides an explanation for the magnetic properties of this, site. The structure of the oxidized C. ammoniagenes R2 also reveals an, additional water molecule bridging the radical and the iron site, which, has not previously been seen in any other R2 structure and which might, have important mechanistic implications.
About this Structure
1KGP is a Single protein structure of sequence from Corynebacterium ammoniagenes with MN as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structure of the di-iron/radical protein of ribonucleotide reductase from Corynebacterium ammoniagenes., Hogbom M, Huque Y, Sjoberg BM, Nordlund P, Biochemistry. 2002 Jan 29;41(4):1381-9. PMID:11802741
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