2i7s | pdb_00002i7s
Crystal structure of Re(phen)(CO)3 (Thr124His)(His83Gln) Azurin Cu(II) from Pseudomonas aeruginosa
Structural highlights
FunctionAZUR_PSEAE Transfers electrons from cytochrome c551 to cytochrome oxidase. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedPhotoinduced 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. Relaxation dynamics of Pseudomonas aeruginosa Re(I)(CO)3(alpha-diimine)(HisX)+ (X = 83, 107, 109, 124, 126)Cu(II) azurins.,Blanco-Rodriguez AM, Busby M, Ronayne K, Towrie M, Gradinaru C, Sudhamsu J, Sykora J, Hof M, Zalis S, Di Bilio AJ, Crane BR, Gray HB, Vlcek A Jr J Am Chem Soc. 2009 Aug 26;131(33):11788-800. PMID:19639996[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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