Cardiolipin binds nonyl acridine orange by aggregating the dye at exposed hydrophobic domains on bilayer surfaces

FEBS Letters

Lutterodt, Lydia²  Dowhan, William¹  Haines, Thomas H.²  Zheng, Donghong²  Birke, Ronald L.²  Mileykovskaya, Eugenia¹ 

[1]University of Texas-Houston Medical School, Houston TX, USA

[2]Department of Chemistry, City College of the City University of New York, 138 Street at Convent Avenue, New York, NY 10031, USA

关键词: 10-N-Nonyl acridine orange;    Cardiolipin;    Fluorescence emission;    Cardiolipin pK;    Lipid phase separation;    Escherichia coli;    NAO;    10-N-nonyl acridine orange;    CL;    cardiolipin;   

DOI  :  10.1016/S0014-5793(01)02948-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

10-N-Nonyl acridine orange (NAO) has been used at low concentrations as a fluorescent indicator for cardiolipin (CL) in membranes and bilayers. The mechanism of its selective fluorescence in the presence of CL, and not any other phospholipids, is not understood. The dye might recognize CL by its high pK (pK ₂>8.5). To investigate that, we established that NAO does not exhibit a pK in a pH range between 2.3 and 10.0. A second explanation is that the dye aggregates at hydrophobic domains on bilayers exposed by the CL. We found that a similar spectral shift occurs in the absence of CL in a concentrated solution of the dye in methanol and in the solid state. A model is proposed in which the nonyl group inserts in the bilayer at the hydrophobic surface generated by the presence of four chains on the phospholipid.

【 授权许可】

Unknown