Synthesis and binding properties of carboxylphenyl-modified calix[4]arenes and cytochrome c.
Two novel carboxylphenyl-modified calix[4]arenes, tetrakis-carboxylphenylcalix[4]arene (TCPC) and 1,3-bis-carboxylphenylcalix[4]arene (BCPC), as well as a corresponding analogue for comparison, tetrakis-phenylcalix[4]arene (TPC), have been synthesized by palladium-catalyzed Suzuki cross-coupling of arylboronic acid and tetrabromocalix[4]arene as a key step. The binding properties of these calix[4]arene derivatives with bovine heart cytochrome c (cyt c) in dimethylformamide (DMF) was investigated by fluorescence spectroscopy. The binding affinity in the order of TCPC>BCPC>>TPC reflects a clear dependence on the number of carboxyl ligating groups attached onto a receptor and suggests the electrostatic force may be the predominant factor driving the complexing process. The stable 1:1 complexes of TCPC and BCPC with cyt c were evidenced with the binding constants of 3.15 x 10(6) and 5.85 x 10(5)L mol(-1), respectively. Due to a large overlap between the emission spectrum of TCPC and the absorption spectrum of cyt c, and a short interaction distance (estimated to be 5.6 nm) between them, the fluorescence quenching of TCPC upon complexation with cyt c is attributed to an efficient energy transfer.
An
Wen Ting
WT
Research Center of Environmental Science and Engineering, Department of Chemistry, Shanxi University, Taiyuan 030006, China.
Jiao
Yong
Y
Sun
Xiao Hua
XH
Zhang
Xiao Ling
XL
Dong
Chuan
C
Shuang
Shao Min
SM
Xia
Ping Fang
PF
Wong
Man Shing
MS
D000818:Animals; D047250:Calixarenes / Q000138:chemical synthesis / Q000737:chemistry*; D002264:Carboxylic Acids; D002417:Cattle; D045304:Cytochromes c / Q000737:chemistry*; D004126:Dimethylformamide; D004735:Energy Transfer; D010636:Phenols / Q000138:chemical synthesis / Q000737:chemistry*; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship
D002264:Carboxylic Acids; D010636:Phenols; C121325:calix(4)arene; D047250:Calixarenes; D004126:Dimethylformamide; D045304:Cytochromes c