5r1r
RIBONUCLEOTIDE REDUCTASE E441A MUTANT R1 PROTEIN FROM ESCHERICHIA COLI
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OverviewOverview
The invariant active site residue Glu441 in protein R1 of ribonucleotide, reductase from Escherichia coli has been engineered to alanine, aspartic, acid, and glutamic acid. Each mutant protein was structurally and, enzymatically characterized. Glu441 contributes to substrate binding, and, a carboxylate side chain at position 441 is essential for catalysis. The, most intriguing results are the suicidal mechanism-based reaction, intermediates observed when R1 E441Q is incubated with protein R2 and, natural substrates (CDP and GDP). In a consecutive reaction sequence, we, observe at least three clearly discernible steps: (i) a rapid decay (k1, >/= 1.2 s-1) of the catalytically essential tyrosyl radical of protein R2, concomitant with formation of an early transient radical intermediate, ... [(full description)]
About this StructureAbout this Structure
5R1R is a [Protein complex] structure of sequences from [Escherichia coli]. Active as [Ribonucleoside-diphosphate reductase], with EC number [1.17.4.1]. Structure known Active Sites: ACA, ACB and ACC. Full crystallographic information is available from [OCA].
ReferenceReference
A new mechanism-based radical intermediate in a mutant R1 protein affecting the catalytically essential Glu441 in Escherichia coli ribonucleotide reductase., Persson AL, Eriksson M, Katterle B, Potsch S, Sahlin M, Sjoberg BM, J Biol Chem. 1997 Dec 12;272(50):31533-41. PMID:9395490
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