Protein Dynamics of Isolated Chains of Recombinant Human Hemoglobin Elucidated by Time-Resolved Resonance Raman Spectroscopy
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- 作者：Kenta Yamada ; Haruto Ishikawa ; Yasuhisa Mizutani
- 刊名：The Journal of Physical Chemistry B
- 出版年：2012
- 出版时间：February 16, 2012
- 年：2012
- 卷：116
- 期：6
- 页码：1992-1998
- 全文大小：455K
- 年卷期：v.116,no.6(February 16, 2012)
- ISSN：1520-5207
文摘
Protein dynamics of isolated chains of recombinant human adult hemoglobin (rHb) following ligand photolysis were studied by time-resolved resonance Raman spectroscopy. In the time-resolved spectra, we observed frequency shifts of the iron鈥揾istidine stretching [谓(Fe-His)] and 纬7 bands and an intensity change of the 谓8 band for both the isolated 伪- and 尾-chains, showing that a primary metastable form was present in the initial tens of nanoseconds following the photolysis. Similar spectral changes were reported for human adult hemoglobin and rHb. Common spectral changes between isolated chains and hemoglobin indicated that structural changes reflected by the spectral changes were characteristic of the hemoglobin subunits. The heme modes suggested that the primary metastable form had a more disordered orientation of propionates and a less strained environment than the deoxy form. The spectral changes of the isolated 伪-chain were faster than those of the 尾-chain. In spite of the fact that the isolated 尾-chain formed a tetramer in a similar fashion to rHb, the spectral changes were much slower than those of rHb. The present study shows that intersubunit interactions affected the rates of the structural changes of the heme pocket. Characteristics of the tertiary structure dynamics of hemoglobin are discussed.