RESONANCE RAMAN INVESTIGATION OF CARBON-MONOXIDE BONDING IN (CARBON MONOXY) HEMOGLOBIN AND (CARBON MONOXY) MYOGLOBIN - DETECTION OF FE-CO STRETCHING AND FE-C-O BENDING VIBRATIONS AND INFLUENCE OF THE QUATERNARY STRUCTURE CHANGE
RESONANCE RAMAN INVESTIGATION OF CARBON-MONOXIDE BONDING IN (CARBON MONOXY) HEMOGLOBIN AND (CARBON MONOXY) MYOGLOBIN - DETECTION OF FE-CO STRETCHING AND FE-C-O BENDING VIBRATIONS AND INFLUENCE OF THE QUATERNARY STRUCTURE CHANGE
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DOI：
10.1021/bi00535a004
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发表时间：
1982-01-01
期刊：
影响因子：
2.9
通讯作者：
YU, NT
中科院分区：
文献类型：
--
作者：
TSUBAKI, M;SRIVASTAVA, RB;YU, NT
本文首次报道了用共振拉曼光谱法直接鉴定一氧化碳血红蛋白（HbCO）和β-肌红蛋白（MbCO）中的Fe-C键。在Soret带内406.7 nm处激发时，在人（一氧化碳）HbA（抹香鲸MbCO）中分别检测到507（512）、578（577）和1951（1944）cm-1处的Fe-CO伸缩振动、Fe. sbd.C.sbd.O弯曲振动和束缚C-O伸缩振动。这些分配是基于同位素13C16O、12C18O和13C18O的频移。根据模型Im. sbd. Fe. sbd. C. sbd. O（而不是Im. sbd. Fe. sbd. O. sbd. C）[Im是咪唑]计算的同位素位移与观测数据吻合得很好。讨论了这些振动的共振拉曼增强的可能机制。（Fe）. sbd..圆周率 * (CO)互动仔细检查在507 cm-1（ρ）处的Fe/CO伸缩模式。= 0.055）在有和没有肌醇六磷酸（IHP）的（一氧化碳）HbA和HbCO堪萨斯中显示频率和强度没有变化。这意味着在Fe. sbd. C键能中没有显著的变化是通过在连接的HbCO堪萨斯中将四级结构从R转换为T形式来诱导的。Fe原子和近端组氨酸之间不存在键张力，这是因为（Fe. sbd.CO）频率对模型血红素. sbd.CO络合物中1-甲基咪唑到1，2-二甲基咪唑（作为第五配体）的变化敏感。然而，鲤鱼HbCO的共振拉曼光谱在R → W时在较低能量侧表现出Fe/CO伸缩模式的加宽。T转化与IHP，表明存在一个新的构象（或构象）与较弱的Fe. sbd. CO键或有点不同的CO扭曲。
The direct identification of the Fe-C bond in (carbon monoxy)hemoglobins (HbCO) and -myoglobin (MbCO) by resonance Raman spectroscopy is reported for the first time. The Fe-CO stretching, Fe.sbd.C.sbd.O bending, and bound C-O stretching vibrations were detected at 507 (512), 578 (577), and 1951 (1944) cm-1, respectively, in human (carbon monoxy)HbA (sperm whale MbCO) upon excitation at 406.7 nm within the Soret band. These assignments were made on the basis of frequency shifts with the isotopes 13C16O, 12C18O, and 13C18O. Calculated isotope shifts according to the model Im.sbd.Fe.sbd.C.sbd.O (but not Im.sbd.Fe.sbd.O.sbd.C) [Im is imidazole] agree well with the observed data. The possible mechanisms of resonance Raman enhancement of these vibrations are discussed in terms of the d.pi.(Fe).sbd..pi.*(CO) interaction. Careful examination of the Fe.sbd.CO stretching mode at 507 cm-1 (.rho. = 0.055) in both (carbon monoxy)HbA and HbCO Kansas with and without inositol hexaphosphate (IHP) reveals no changes in frequency and intensity. This implies that no significant change in the Fe.sbd.C bond energy is induced by switching the quaternary structure from the R to the T form in ligated HbCO Kansas. The absence of bond tension between the Fe atom and the proximal histidine is suggested, as the .nu.(Fe.sbd.CO) frequency is sensitive to a change from 1-methylimidazole to 1,2-dimethylimidazole (as fifth ligand) in model heme.sbd.CO complexes. However, the resonance Raman spectrum of carp HbCO exhibits a broadening of the Fe.sbd.CO stretching mode on the lower energy side upon R .fwdarw. T conversion with IHP, suggesting the presence of a new conformer (or conformers) with a weaker Fe.sbd.CO bond or a somewhat different CO distortion.