Simultaneous observation of the O-O and Fe-O2 stretching modes in oxyhemoglobins
Simultaneous observation of the O-O and Fe-O2 stretching modes in oxyhemoglobins
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DOI：
10.1073/pnas.98.2.479
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发表时间：
2001-01-16
影响因子：
11.1
通讯作者：
Rousseau, DL
中科院分区：
文献类型：
--
作者：
Das, TK;Couture, M;Rousseau, DL
了解氧合血红蛋白的双氧部分的化学性质对于阐明其生理功能至关重要。在目前的工作中，直接拉曼光谱观察的Fe-O-2和O-O伸缩模式明确地建立了在Chlamydiaeugametos和集胞藻PCC 6803的血红蛋白中的氧结合血红素部分的振动特性。除了提供含铁卟啉的氧合血红蛋白中O-O伸缩模的共振拉曼归属（衣原体为1136 cm（-1），集胞藻为1133 cm（-1）），本研究还报告了Fe-O-2伸缩模的异常低频率（554 cm（-1））。Fe-O-2伸缩模式对远端残基突变的频率变化证实了与结合氧的强氢键作用。这些发现表明这些血红蛋白具有酶功能，而不是氧运输作用。
Understanding of the chemical nature of the dioxygen moiety of oxyhemoglobin is crucial for elucidation of its physiological function. In the present work, direct Raman spectroscopic observation of both the Fe-O-2 and O-O stretching modes unambiguously establishes the vibrational characteristics of the oxygen-bound heme moiety in the hemoglobins of Chlamydomonas eugametos and Synechocystis PCC6803. In addition to providing the resonance Raman assignment of the O-O stretching mode (1136 cm(-l) for Chlamydomonas, 1133 cm(-1) for Synechocystis) in an oxyhemoglobin with an iron-porphyrin, this study also reports unusually low frequencies for the Fe-O-2 stretching modes (554 cm(-l)). The effect of strong hydrogen bonding to the bound oxygen is confirmed by changes in the frequency of the Fe-O-2 stretching mode on mutation of distal residues, These findings suggest an enzymatic function rather than an oxygen transport role for these hemoglobins.