Relaxation Dynamics of Pseudomonas aeruginosa ReI ( CO ) 3 ( r-diimine ) ( HisX ) + ( X )
Relaxation Dynamics of Pseudomonas aeruginosa ReI ( CO ) 3 ( r-diimine ) ( HisX ) + ( X )
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铜绿假单胞菌 ReI (CO ) 3 ( r-二亚胺 ) ( HisX ) ( X ) 的弛豫动力学
DOI：
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发表时间：
2009
期刊：
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通讯作者：
A. Vlček
中科院分区：
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作者：
Michael Busby;K. Ronayne;M. Towrie;C. Gradinaru;J. Sudhamsu;J. Sýkora;M. Hof;S. Záliš;A. J. D. Bilio;B. Crane;H. Gray;A. Vlček
用时间分辨(PS-ns)红外光谱和发射光谱研究了5种结构表征的铜绿假单胞菌Re(CO)3(R-二亚胺)(HisX)(X)83,107,109,124,126)CuII天青的光诱导弛豫过程。晶体结构揭示了重天青二聚体和三聚体的存在，在两种情况下(X)107,124)涉及交错的二亚胺芳环之间的范德华相互作用。随时间变化的发射各向异性测量证实，蛋白质在MM溶液(D2O，KPI缓冲液，PD)7.1中聚集。激发态密度泛函理论计算表明，在Re(CO)3f二亚胺3MLCT态中发生了广泛的电荷再分布：这种3MLCT态的激发引发了重天青的几个驰豫过程，其动力学强烈地依赖于金属标记在蛋白质表面的位置。弛豫表现为激发态ν(CO)IR谱带的动态蓝移，这些蓝移符合三指数动力学：分子内的振动重分布与振动和溶剂松弛一起产生Subps、∼2和8-20ps组分，而∼102ps的动力学归因于Re(CO)3(Phen)(Im)单元相对于肽链的位移(重定向)，这优化了REI激发态电子密度与溶剂化多肽的库仑相互作用。证据还表明，在不干扰反应场或与多肽相互作用的情况下，重新承载链的额外节段性运动发生。我们的工作表明，REI-羰基二亚胺络合物的时间分辨红外光谱和发射各向异性是研究蛋白质表面和蛋白质-蛋白质界面区域及其周围分子动力学的有力探针。
Photoinduced relaxation processes of five structurally characterized Pseudomonas aeruginosa Re(CO)3(R-diimine)(HisX) (X ) 83, 107, 109, 124, 126)CuII 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 (D2O, KPi buffer, pD ) 7.1). Excited-state DFT calculations show that extensive charge redistribution in the Re(CO)3f diimine 3MLCT state occurs: excitation of this 3MLCT 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 ν(CO) IR bands that occur with triexponential kinetics: intramolecular vibrational redistribution together with vibrational and solvent relaxation give rise to subps, ∼2, and 8-20 ps components, while the ∼102 ps kinetics are attributed to displacement (reorientation) of the Re(CO)3(phen)(im) unit relative to the peptide chain, which optimizes Coulombic interactions of the ReI excited-state electron density with solvated peptide groups. Evidence also suggests that additional segmental movements of Re-bearing -strands occur without perturbing the reaction field or interactions with the peptide. Our work demonstrates that time-resolved IR spectroscopy and emission anisotropy of ReI carbonyl-diimine complexes are powerful probes of molecular dynamics at or around the surfaces of proteins and protein-protein interfacial regions.