5r1r
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:5r1r.gif|left|200px]] | [[Image:5r1r.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_5r1r", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | | | + | --> |
| - | | | + | {{STRUCTURE_5r1r| PDB=5r1r | SCENE= }} |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''RIBONUCLEOTIDE REDUCTASE E441A MUTANT R1 PROTEIN FROM ESCHERICHIA COLI''' | '''RIBONUCLEOTIDE REDUCTASE E441A MUTANT R1 PROTEIN FROM ESCHERICHIA COLI''' | ||
| Line 28: | Line 25: | ||
[[Category: Eklund, H.]] | [[Category: Eklund, H.]] | ||
[[Category: Eriksson, M.]] | [[Category: Eriksson, M.]] | ||
| - | [[Category: | + | [[Category: Allosteric regulation]] |
| - | [[Category: | + | [[Category: Deoxyribonucleotide synthesis]] |
| - | + | [[Category: Radical chemistry]] | |
| - | [[Category: | + | [[Category: Ribonucleotide reductase]] |
| - | [[Category: | + | [[Category: Specificity]] |
| - | [[Category: | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 22:37:17 2008'' |
| - | + | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 19:37, 4 May 2008
RIBONUCLEOTIDE REDUCTASE E441A MUTANT R1 PROTEIN FROM ESCHERICHIA COLI
Overview
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.
About this Structure
5R1R is a Protein complex structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.
Reference
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 Page seeded by OCA on Sun May 4 22:37:17 2008
