1jzj
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Pseudomonas aeruginosa Azurin Os(bpy)2(im)(His83)
OverviewOverview
Rates of reduction of Os(III), Ru(III), and Re(I) by Cu(I) in, His83-modified Pseudomonas aeruginosa azurins (M-Cu distance approximately, 17 A) have been measured in single crystals, where protein conformation, and surface solvation are precisely defined by high-resolution X-ray, structure determinations: 1.7(8) x 10(6) s(-1) (298 K), 1.8(8) x 10(6), s(-1) (140 K), [Ru(bpy)2(im)(3+)-]; 3.0(15) x 10(6) s(-1) (298 K), [Ru(tpy)(bpy)(3+)-]; 3.0(15) x 10(6) s(-1) (298 K), [Ru(tpy)(phen)(3+)-];, 9.0(50) x 10(2) s(-1) (298 K), [Os(bpy)2(im)(3+)-]; 4.4(20) x 10(6) s(-1), (298 K), [Re(CO)3(phen)(+)] (bpy = 2,2'-bipyridine; im = imidazole; tpy =, 2,2':6',2' '-terpyridine; phen = 1,10-phenanthroline). The time constants, for electron tunneling in crystals are roughly the same as those measured, in solution, indicating very similar protein structures in the two states., High-resolution structures of the oxidized (1.5 A) and reduced (1.4 A), states of Ru(II)(tpy)(phen)(His83)Az establish that very small changes in, copper coordination accompany reduction but reveal a shorter axial, interaction between copper and the Gly45 peptide carbonyl oxygen [2.6 A, for Cu(II)] than had been recognized previously. Although, Ru(bpy)2(im)(His83)Az is less solvated in the crystal, the reorganization, energy for Cu(I) --> Ru(III) electron transfer falls in the range (0.6-0.8, eV) determined experimentally for the reaction in solution. Our work, suggests that outer-sphere protein reorganization is the dominant, activation component required for electron tunneling.
About this StructureAbout this Structure
1JZJ is a Single protein structure of sequence from Pseudomonas aeruginosa with CU, DOS, LOS and IME as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Electron tunneling in single crystals of Pseudomonas aeruginosa azurins., Crane BR, Di Bilio AJ, Winkler JR, Gray HB, J Am Chem Soc. 2001 Nov 28;123(47):11623-31. PMID:11716717
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