Linear dichroism study of metalloporphyrin transition moments in view of radiationless interactions with tryptophan in hemoproteins.
Linear dichroism study of metalloporphyrin transition moments in view of radiationless interactions with tryptophan in hemoproteins.
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鉴于与血红蛋白中色氨酸的无辐射相互作用，金属卟啉转变矩的线性二色性研究。
DOI：
10.1111/j.1751-1097.1993.tb04920.x
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发表时间：
1993
影响因子：
3.3
通讯作者：
Kuśba,J
中科院分区：
文献类型：
--
作者：
Gryczynski,Z;Bucci,E;Kuśba,J
我们测量了几种嵌入在拉伸聚乙烯醇(PVA)薄膜中的金属卟啉的线性二色性，以估计吸收跃迁矩的方向，这些吸收跃迁矩与色氨酸和血红素之间的无辐射能量转移有关。金属卟啉是原卟啉IX(PPIX)的衍生物，分别是Fe3+-PPIX(铁血红素)和Fe2+CO-PPIX(CO-血红素)，镁-PPIX(镁-血红素)和锌-PPIX(锌-血红素)。测量在300到700 nm之间进行。在所有情况下，线性二向色性都是波长相关的，这表明存在几个不同取向的转变时刻。我们将注意力集中在近紫外光(300380 Nm)和索雷特(380450 Nm)吸收带上。以高斯分量表示的去卷积得到了380-450 nm之间的三个分量，而在300-380 nm区域只有一个分量。氧、脱氧和单碳氧合血红蛋白的近UV和Soret光谱的去卷积得到了非常相似的结果，表明游离和蛋白质包埋的血红素的各种转变时刻的方向非常相似。应该强调的是，单一的300-380 nm带是唯一负责调节血红蛋白中从色氨酸到血红素的能量转移的重叠积分的带(Gryczynski等人，生物物理。J.63,648-653,1992)。这一单一谱带的二色性表明，它的转变力矩与血红素部分的α-γ中观轴取向约60。我们的结论是，当血红素作为色氨酸能量传递的受体时，它应该被认为是一个线性振子。
We measured the linear dichroism of several metalloporphyrins embedded in stretched polyvinyl alcohol (PVA) films to estimate the orientation of the absorption transition moments, which in hemoproteins are relevant to the radiationless energy transfer between tryptophan and heme. The metalloporphyrins were derivatives of protoporphyrin IX (PPIX), namely Fe3+‐PPIX (ferric‐heme) and Fe2+CO‐PPIX (CO‐heme), Mg‐PPIX (Mg‐heme) and Zn‐PPIX (Zn‐heme). Measurements were conducted between 300 and 700 nm. In all cases the linear dichroism was wavelength dependent, indicating the presence of several transition moments with different orientations. We focused our attention on the near‐UV (300–380 nm) and Soret (380450 nm) absorption bands. Deconvolution in terms of Gaussian components gave three components between 380 and 450 nm and only one in the 300–380 nm region. Deconvolution of the near‐UV and Soret spectra of oxy‐, deoxy‐ and carbonmonoxyhemoglobin gave very similar results, suggesting a very similar orientation of the various transition moments in the free and protein‐embedded hemes. It should be stressed that the single 300–380 nm band is the only one responsible for the overlap integral that regulates the energy transfer from tryptophan to heme in hemoproteins (Gryczynskiet al., Biophys. J. 63, 648–653, 1992). The dichroism of this single band indicated that its transition moment is oriented at about 60 from the α‐γ meso‐axis of the heme moiety. We conclude that the heme should be considered a linear oscillator when it acts as acceptor of energy transfer from tryptophans.