1
|
Jiang B, Cai S, Xie J, Feng FM. Nuclease Activity of Diaza-Crown Ether Complexes of Cerium(III) with Different Functional Groups as Side Arms. PROGRESS IN REACTION KINETICS AND MECHANISM 2018. [DOI: 10.3184/146867818x15161889114448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cerium(III) complexes of two ligands of a diaza-crown ether with different functional groups as side arms were synthesised and characterised. The catalytic ability of the cerium(III) complexes for pUC19 DNA cleavage was investigated and compared using agarose gel electrophoresis. The results indicate that the catalytic activity of the complex CeL2 [L2 = 2,2′- (1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl) diacetamide] with two carbamoylmethyl groups is significantly higher than the complex CeL1 [L1 = 2,2′- (1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl) diethanol] with two hydroxyethyl groups under the same conditions. The optimum catalytic concentrations of CeL1 and CeL2 were 7.69 × 10−5 and 3.08 × 10−5 mol L−1 respectively and excessively high concentrations of the complexes can reduce their catalytic efficiency due to the formation of inactive μ-hydroxo dimers. The optimum catalytic acidities of CeL1 and CeL2 were pH 7.0 and 7.5 respectively and excessively high pH of the reaction system can reduce the catalytic efficiency of the complexes due to the formation of cerium(III) hydroxide. DNA cleavage promoted by the two complexes takes place via the same hydrolytic pathway and so the activity difference of the two complexes is attributed to the stability of the complexes, rather than the catalytic mechanism.
Collapse
Affiliation(s)
- Bingying Jiang
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054, P.R. China
| | - Shulan Cai
- College of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, Sichuan 643000, P.R. China
| | - Jiaqing Xie
- College of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, Sichuan 643000, P.R. China
| | - Fa-Mei Feng
- College of Chemistry and Environmental Engineering, Sichuan University of Science and Engineering, Zigong, Sichuan 643000, P.R. China
| |
Collapse
|
2
|
Li FZ, Xie JQ, Cai SL, Feng FM. Comparison of catalytic activities of new La (III) and Ce (III) complexes with different diaza-crown ether ligands for DNA hydrolytic cleavage. PROGRESS IN REACTION KINETICS AND MECHANISM 2016. [DOI: 10.3184/146867816x14698928943442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A new diaza-crown ether with double hydroxypropyl branches (L = 1,1'-(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)dipropan-2-ol) and its two lanthanide complexes (LaL and CeL) were synthesised and characterised. Their nuclease activities on pUC19 DNA cleavage were investigated using agarose gel electrophoresis, and pseudo-first-order rate constants kobs of 0.067 h–1 for LaL, 0.041 h–1 for CeL, 0.013 h–1 for LaL0, and 0.027 h–1 CeL0 were obtained (L0 = 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane). The results indicated that the CeL complex was more efficient than the LaL complex for DNA cleavage at low concentrations, but the LaL complex was more efficient than the CeL complex at high concentrations. Moreover, kinetic studies demonstrated that introducing hydroxypropyl side arms in the ring of the diaza-crown ether can improve the catalytic ability of the complexes in DNA cleavage, which may be due to the hydroxypropyl side arms enhancing the bonding interaction between the complex and the DNA molecule by hydrogen bonding. A hydrolytic mechanism for DNA cleavage was demonstrated by applying several oxygen scavengers to the DNA catalytic cleavage. A proposed mechanism for the DNA cleavage shows that the hydroxypropyl side groups can recognise and bind the phosphodiester bond of DNA by hydrogen bonding and electrostatic interaction.
Collapse
Affiliation(s)
- Fang-zhen Li
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054
| | - Jia-qing Xie
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054
| | - Shu-lan Cai
- College of Chemistry and Pharmaceutical Engineering, Sichuan University of Science and Engineering, Zigong, Sichuan 643000, P.R. China
| | - Fa-mei Feng
- College of Chemistry and Pharmaceutical Engineering, Sichuan University of Science and Engineering, Zigong, Sichuan 643000, P.R. China
| |
Collapse
|