Laboratoire d'Optique et Biosciences, INSERM, Ecole Polytechnique, 91128 Palaiseau, France.
J Phys Chem B. 2012 Apr 5;116(13):4106-14. doi: 10.1021/jp300849y. Epub 2012 Mar 19.
To study the ultrafast movement of the heme iron induced by nitric oxide (NO) binding to hemoglobin (Hb) and myoglobin (Mb), we probed the picosecond spectral evolution of absorption band III (∼760 nm) and vibrational modes (iron-histidine stretching, ν(4) and ν(7) in-plane modes) in time-resolved resonance Raman spectra. The time constants of band III intensity kinetics induced by NO rebinding (25 ps for hemoglobin and 40 ps for myoglobin) are larger than in Soret bands and Q-bands. Band III intensity kinetics is retarded with respect to NO rebinding to Hb and to Mb. Similarly, the ν((Fe-His)) stretching intensity kinetics are retarded with respect to the ν(4) and ν(7) heme modes and to Soret absorption. In contrast, band III spectral shift kinetics do not coincide with band III intensity kinetics but follows Soret kinetics. We concluded that, namely, the band III intensity depends on the heme iron out-of-plane position, as theoretically predicted ( Stavrov , S. S. Biopolymers 2004 , 74 , 37 - 40 ).
为了研究一氧化氮（NO）与血红蛋白（Hb）和肌红蛋白（Mb）结合诱导的亚铁血红素超快运动，我们探测了吸收带 III（约 760nm）和振动模式（铁-组氨酸伸缩，ν(4)和 ν(7)面内模式）在时间分辨共振拉曼光谱中的皮秒光谱演化。由 NO 再结合诱导的带 III 强度动力学的时间常数（血红蛋白为 25 ps，肌红蛋白为 40 ps）大于 Soret 带和 Q 带。带 III 强度动力学相对于 Hb 和 Mb 中的 NO 再结合被延迟。同样，ν((Fe-His))伸缩强度动力学相对于 ν(4)和 ν(7)血红素模式和 Soret 吸收被延迟。相比之下，带 III 光谱位移动力学与带 III 强度动力学不同步，而是遵循 Soret 动力学。我们得出结论，即带 III 强度取决于亚铁血红素的面外位置，这与理论预测一致（Stavrov, S. S. Biopolymers 2004, 74, 37 - 40）。
