磷脂双分子层中光致变色螺吡喃分子开关的异构化动力学

Isomerization dynamics of photochromic spiropyran molecular switches in phospholipid bilayers.

作者信息

Wohl Christopher J, Kuciauskas Darius

机构信息

Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, Virginia 23284-2006, USA.

出版信息

J Phys Chem B. 2005 Nov 24;109(46):21893-9. doi: 10.1021/jp0538823.

DOI:10.1021/jp0538823

PMID:16853844

Abstract

Transient absorption spectroscopy was used to investigate the dynamics of the photochromic indolinobenzospiropyran reaction in toluene solution and in phosphatidylcholine bilayers (1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)). After excitation with UV light, colorless (R/S)-2-(3',3'-dimethyl-6-nitro-3'H-spiro[chromene-2,2'-indol]-1'-yl)ethanol derivatives are converted to colored merocyanine products in high yield; Phi = 0.45 in DMPC liposomes. We find that the reaction occurs in the bilayer aliphatic region in the gel (P(beta)(')) and liquid (L(alpha)) phases. The Arrhenius activation energy for the isomerization in DMPC bilayers was approximately 3.5 times larger in the liquid phase (L(alpha), E(a) = 26.0 +/- 1.0 kJ mol(-1)) than that in the gel phase (P(beta)('), E(a) = 7.3 +/- 1.6 kJ mol(-1)). Analysis of the isomerization rate constant temperature dependence allows an estimation of the bilayer viscosity and free volume properties in the L(alpha) phase.

摘要

瞬态吸收光谱法用于研究光致变色吲哚啉苯并螺吡喃反应在甲苯溶液和磷脂酰胆碱双层膜（1,2-二肉豆蔻酰-sn-甘油-3-磷酸胆碱（DMPC）、1,2-二棕榈酰-sn-甘油-3-磷酸胆碱（DPPC）和1,2-二油酰-sn-甘油-3-磷酸胆碱（DOPC））中的动力学。用紫外光激发后，无色的（R/S）-2-（3',3'-二甲基-6-硝基-3'H-螺[色烯-2,2'-吲哚]-1'-基）乙醇衍生物以高产率转化为有色部花青产物；在DMPC脂质体中，Φ = 0.45。我们发现该反应发生在凝胶态（P(β)'）和液态（L(α)）相的双层脂肪族区域。DMPC双层膜中异构化的阿仑尼乌斯活化能在液相（L(α)，E(a) = 26.0 ± 1.0 kJ mol⁻¹）中比在凝胶相（P(β)'，E(a) = 7.3 ± 1.6 kJ mol⁻¹）中大约大３.５倍。对异构化速率常数温度依赖性的分析允许估计L(α)相中的双层粘度和自由体积性质。