2I7S

Crystal structure of Re(phen)(CO)3 (Thr124His)(His83Gln) Azurin Cu(II) from Pseudomonas aeruginosa

Summary for 2I7S

• Entry DOI: 10.2210/pdb2i7s/pdb
• Related: 1BEX
• Descriptor: Azurin, COPPER (II) ION, (1,10 PHENANTHROLINE)-(TRI-CARBON MONOXIDE) RHENIUM (I), ... (5 entities in total)
• Functional Keywords: azurin, rhenium, electron transfer in proteins, electron transport
• Biological source: Pseudomonas aeruginosa
• Cellular location: Periplasm: P00282
• Total number of polymer chains: 4
• Total formula weight: 58134.37

Authors

Gradinaru, C.,Crane, B.R. (deposition date: 2006-08-31, release date: 2006-12-05, Last modification date: 2024-11-06)

Primary citation

Blanco-Rodriguez, A.M.,Busby, M.,Ronayne, K.,Towrie, M.,Gradinaru, C.,Sudhamsu, J.,Sykora, J.,Hof, M.,Zalis, S.,Di Bilio, A.J.,Crane, B.R.,Gray, H.B.,Vlcek, A.
Relaxation dynamics of Pseudomonas aeruginosa Re(I)(CO)3(alpha-diimine)(HisX)+ (X = 83, 107, 109, 124, 126)Cu(II) azurins.
J.Am.Chem.Soc., 131:11788-11800, 2009

PubMed Abstract: Photoinduced relaxation processes of five structurally characterized Pseudomonas aeruginosa Re(I)(CO)(3)(alpha-diimine)(HisX) (X = 83, 107, 109, 124, 126)Cu(II) azurins have been investigated by time-resolved (ps-ns) IR spectroscopy and emission spectroscopy. Crystal structures reveal the presence of Re-azurin dimers and trimers that in two cases (X = 107, 124) involve van der Waals interactions between interdigitated diimine aromatic rings. Time-dependent emission anisotropy measurements confirm that the proteins aggregate in mM solutions (D(2)O, KP(i) buffer, pD = 7.1). Excited-state DFT calculations show that extensive charge redistribution in the Re(I)(CO)(3) --> diimine (3)MLCT state occurs: excitation of this (3)MLCT state triggers several relaxation processes in Re-azurins whose kinetics strongly depend on the location of the metallolabel on the protein surface. Relaxation is manifested by dynamic blue shifts of excited-state nu(CO) IR bands that occur with triexponential kinetics: intramolecular vibrational redistribution together with vibrational and solvent relaxation give rise to subps, approximately 2, and 8-20 ps components, while the approximately 10(2) ps kinetics are attributed to displacement (reorientation) of the Re(I)(CO)(3)(phen)(im) unit relative to the peptide chain, which optimizes Coulombic interactions of the Re(I) excited-state electron density with solvated peptide groups. Evidence also suggests that additional segmental movements of Re-bearing beta-strands occur without perturbing the reaction field or interactions with the peptide. Our work demonstrates that time-resolved IR spectroscopy and emission anisotropy of Re(I) carbonyl-diimine complexes are powerful probes of molecular dynamics at or around the surfaces of proteins and protein-protein interfacial regions.

PubMed: 19639996
DOI: 10.1021/ja902744s

Experimental method

X-RAY DIFFRACTION (1.35 Å)