6R1R

RIBONUCLEOTIDE REDUCTASE E441D MUTANT R1 PROTEIN FROM ESCHERICHIA COLI

6R1R の概要

• エントリーDOI: 10.2210/pdb6r1r/pdb
• 分子名称: RIBONUCLEOTIDE REDUCTASE R1 PROTEIN, RIBONUCLEOTIDE REDUCTASE R2 PROTEIN (3 entities in total)
• 機能のキーワード: ribonucleotide reductase, deoxyribonucleotide synthesis, radical chemistry, allosteric regulation, specificity, complex (oxidoreductase-peptide), complex (oxidoreductase-peptide) complex, complex (oxidoreductase/peptide)
• 由来する生物種: Escherichia coli; 詳細
• タンパク質・核酸の鎖数: 7
• 化学式量合計: 266674.75

構造登録者

Eriksson, M.,Eklund, H. (登録日: 1997-09-17, 公開日: 1998-03-18, 最終更新日: 2024-10-16)

主引用文献

Persson, A.L.,Eriksson, M.,Katterle, B.,Potsch, S.,Sahlin, M.,Sjoberg, B.M.
A new mechanism-based radical intermediate in a mutant R1 protein affecting the catalytically essential Glu441 in Escherichia coli ribonucleotide reductase.
J.Biol.Chem., 272:31533-31541, 1997

PubMed Abstract: 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 species, (ii) a slower decay (k2 = 0.03 s-1) of the early intermediate concomitant with formation of another intermediate with a triplet EPR signal, and (iii) decay (k3 = 0.004 s-1) of the latter concomitant with formation of a characteristic substrate degradation product. The characteristics of the triplet EPR signal are compatible with a substrate radical intermediate (most likely localized at the 3'-position of the ribose moiety of the substrate nucleotide) postulated to occur in the wild type reaction mechanism as well.

PubMed: 9395490
DOI: 10.1074/jbc.272.50.31533

実験手法

X-RAY DIFFRACTION (3.1 Å)