Emissive Enhancement of the Singlet Oxygen Chemiluminescence Probe after Binding to Bovine Serum Albumin

Molecules

Jon Miranda-Apodaca¹  JuanB. Arellano¹  Adrián Velázquez-Campoy²  Doron Shabat³  Nir Hananya³ 

[1]Departamento de Estrés Abiótico, Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA-CSIC), 37008 Salamanca, Spain

[2]Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain

[3]School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel

关键词: chemically initiated electron exchange process;    chemiluminescence;    isothermal titration calorimetry;    Schaap’s dioxetanes;    singlet oxygen;    SOCL;    bovine serum albumin;   

DOI  :  10.3390/molecules24132422

来源: DOAJ

【 摘 要 】

A chemiluminescence probe for singlet oxygen ¹O₂ (SOCL) was investigated in phosphate buffer saline (PBS), either in the absence of proteins or containing bovine serum albumin (BSA). In the protein-free PBS, the reactivity of SOCL for methylene blue (MB)-photosensitized ¹O₂ was found to be moderate or low. The reaction yield increased with temperature and/or concentration of dissolved molecular oxygen. Unexpectedly, the presence of BSA boosted both the emissive nature and the thermal stability of the phenoxy-dioxetane intermediate formed in the chemiexcitation pathway. Isothermal titration calorimetry showed that SOCL has a moderate binding affinity for BSA and that entropy forces drive the formation of the SOCL-BSA complex. A model with two identical and independent binding sites was used to fit the binding isotherm data. Co-operative binding was observed when MB was present. Local viscosity factors and/or conformational restrictions of the BSA-bound SOCL phenoxy-dioxetane were proposed to contribute to the formation of the highly emissive benzoate ester during the chemically initiated electron exchange luminescence (CIEEL) process. These results led us to conclude that hydrophobic interactions of the SOCL with proteins can modify the emissive nature of its phenoxy-dioxetane, which should be taken into account when using SOCL or its cell-penetrating peptide derivative in living cells.

【 授权许可】

Unknown