1JZJ

Pseudomonas aeruginosa Azurin Os(bpy)2(im)(His83)

Summary for 1JZJ

• Entry DOI: 10.2210/pdb1jzj/pdb
• Related: 1JZE 1JZF 1JZG 1JZH 1JZI
• Descriptor: azurin, COPPER (II) ION, DELTA-BIS(2,2'-BIPYRIDINE)IMIDAZOLE OSMIUM (II), ... (6 entities in total)
• Functional Keywords: blue-copper, electron transfer, tunneling, osmium, electron transport
• Biological source: Pseudomonas aeruginosa
• Cellular location: Periplasm: P00282
• Total number of polymer chains: 2
• Total formula weight: 30760.76

Authors

Crane, B.R.,Di Bilio, A.J.,Winkler, J.R.,Gray, H.B. (deposition date: 2001-09-16, release date: 2001-10-24, Last modification date: 2023-08-16)

Primary citation

Crane, B.R.,Di Bilio, A.J.,Winkler, J.R.,Gray, H.B.
Electron tunneling in single crystals of Pseudomonas aeruginosa azurins.
J.Am.Chem.Soc., 123:11623-11631, 2001

PubMed Abstract: 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.

PubMed: 11716717
DOI: 10.1021/ja0115870

Experimental method

X-RAY DIFFRACTION (1.8 Å)