Stabilization of P4502B4 by its association with P450 1A2 revealed by high-pressure spectroscopy
Stabilization of P4502B4 by its association with P450 1A2 revealed by high-pressure spectroscopy
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DOI：
10.1006/bbrc.2000.3596
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发表时间：
2000-10-05
影响因子：
3.1
通讯作者：
Hoa, GHB
中科院分区：
文献类型：
--
作者：
Davydov, DR;Petushkova, NA;Hoa, GHB
我们研究了细胞色素P450 1A 2（CYP 1A 2）和2B 4（CYP 2B 4）之间的分子间相互作用对血红素蛋白的羰基亚铁络合物的正压失活的影响。当单独考虑时，这些血红素蛋白显示出非常明显的正压行为。2B 4（Fe ~（2+））-CO络合物对流体静压力非常敏感，在相当低的压力下（P ~（-1/2）= 297 MPa，Δ V ~（-0）= -61 ml/mol）发生P450 → P420的转变，而1A 2（Fe ~（2+））-CO对正压失活有极强的抵抗力。仅约8%的1A 2暴露于压力诱导的P450 -> P420转变（P-1/2 = 420 MPa，Δ V-0 = -28 ml/mol）。发现2B 4和1A 2的混合低聚物的形成对2B 4的正压行为有显著的影响。在1A 2和2B 4的异源寡聚体中，2B 4血红素蛋白似乎在很大程度上受到正压失活的保护。在1：1混合低聚物中，不超过25%的总P450含量经历P450 -> P420失活，摩尔反应体积值（Δ V-0 = -26 ml/mol）类似于纯1A 2中发现的那些。此外，1A 2和2B 4之间的相互作用导致的位移的Soret带的亚铁羰基复合物的CYP 2B 4到较短的波长（从451.3至448.4 nm），并大大加强了Soret带波数的静水压力低于200 MPa的依赖性。该效应表明CYP 2B 4血红素部分响应于与CYP 1A 2的相互作用而发生重要水合作用。我们讨论了这些结果的假设，即在微粒体中的细胞色素P450的异源寡聚化的活性和耦合的微粒体单加氧酶的控制中起着重要的作用。(C)北京大学出版社.
We studied the effect of intermolecular interactions between cytochromes P450 1A2 (CYP1A2) and 2B4 (CYP2B4) on the barotropic inactivation of the ferrous carbonyl complexes of the hemoproteins. When taken separately, these hemoproteins reveal quite distinct barotropic behavior. While the 2B4(Fe2+)-CO complex is very sensitive to hydrostatic pressures and undergoes P450 --> P420 transition at rather low pressures (P-1/2 = 297 MPa, Delta V-0 = -61 ml/mol), the 1A2(Fe2+)-CO is extremely resistant to barotropic inactivation. Only about 8% of the 1A2 was exposed to pressure-induced P450 --> P420 transition (P-1/2 = 420 MPa, Delta V-0 = -28 ml/mol). The formation of the mixed oligomers of 2B4 and 1A2 was found to have a dramatic effect on the barotropic behavior of 2B4. In the heterooligomers of 1A2 and 2B4, the 2B4 hemoprotein appears to be largely protected from barotropic inactivation. In 1:1 mixed oligomers no more than 25% of the total P450 content undergoes P450 --> P420 inactivation with the molar reaction volume value (Delta V-0 = -26 ml/mol) similar to those found for pure 1A2. Moreover, interactions between 1A2 and 2B4 results in a displacement of the Soret band of the ferrous carbonyl complex of CYP2B4 to shorter wavelength (from 451.3 to 448.4 nm) and largely strengthens the dependence of the Soret band wavenumber on hydrostatic pressure below 200 MPa. This effect suggests an important hydration of the CYP2B4 heme moiety in response to the interactions with CYP1A2. We discuss these results in terms of the hypothesis that the heterooligomerization of cytochromes P450 in microsomes plays an important role in the control of the activity and coupling of the microsomal monooxygenase. (C) 2000 Academic Press.