Greatly enhanced binding of a cationic porphyrin towards bovine serum albumin by cucurbit[8]uril

• Published in: Physical chemistry chemical physics : PCCP Vol. 12; no. 4; pp. 13255 - 1326
• Main Authors: Lei, Wanhua, Jiang, Guoyu, Zhou, Qianxiong, Zhang, Baowen, Wang, Xuesong
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.01.2010
• Subjects: Animals; Cations - chemistry; Cattle; Chemistry; Exact sciences and technology; General and physical chemistry; Macrocyclic Compounds - chemistry; Magnetic Resonance Spectroscopy; Microscopy, Atomic Force; Photosensitizing Agents - chemistry; Porphyrins - chemistry; Protein Binding; Serum Albumin, Bovine - chemistry; Spectrometry, Fluorescence; Binding; Atomic force microscopy; Bovine; Nitrogen heterocycle; Ternary complex; Light scattering; Fluorescence; Tryptophan; NMR spectrometry; Serum albumin; Protein; Vertebrata; Pyridinium compounds; Mammalia; Dynamics; Porphyrin; Residue; Affinity; Artiodactyla; Ungulata; Porphyrin derivatives; Sensitizer
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c001013h

Binding affinity towards serum albumin and intracellular proteins is of importance for a photodynamic therapy (PDT) sensitizer to selectively localize in tumours and efficiently induce cell death. In this paper, it was found that cucurbit[8]uril (CB8) can greatly improve the binding affinity of 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetra( p -toluenesulfonate) (TMPyP), a promising PDT photosensitizer, towards bovine serum albumin (BSA). Absorption, fluorescence emission, 1 H NMR, dynamic light scattering, atomic force microscope, as well as protein photocleavage measurements suggest that the binding enhancement originates from the formation of a ternary complex of CB8·TMPyP·tryptophan residues. This finding opens up a new approach for the development of more efficient PDT agents. Cucurbit[8]uril (CB8) can greatly improve the binding affinity of a cationic porphyrin (TMPyP) towards bovine serum albumin (BSA).