[Study on the binding mode of sulfated chitosans with nucleic acids using spectral analysis].
The interaction of two kinds of sulfated chitosans with DNA was investigated using fluorescence spectra, absorption spectra, alkaline denaturation curves, ionic strength, fluorescence quenching etc. The results showed that there were two modes of the interaction between sulfated chitosans and DNA/ ethidium bromide (EB): intercalative and electrostatic binding. Hyperchromic and bathochromic effects in the absorption spectra were observed when sulfated chitosans with a low degree of substitution (CT-L) or a high degree of substitution (CT-L) were bound to herring sperm DNA. The stability of DNA/EB was increased with the increase in alkaline denaturation pH in the presence of CT-H and CT-L. Meanwhile, a weak interaction of cationic Mg2+ and phosphate groups of DNA by electrostatic force binding was observed. The fluorescence was efficiently quenched in the presence of a micro-amounts of sulfated chitosans, which confirmed that there was a strong competitive binding interaction among EB, CT-H or CT-L and DNA. All of these demonstrated that different sulfated chitosans can be used as a type of hopeful target-pointed molecule of gene therapy.
Zhang
Hai-Rong
HR
Institute of Biochemical Analysis, Xinzhou Teachers University, Xinzhou 034000, China. biochem@xztc.edu.cn
Guo
Si-Yuan
SY
Li
Lin
L
Cai
Miao-Yan
MY
Zheng
Bi-Sheng
BS
D000818:Animals; D048271:Chitosan / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004996:Ethidium / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
C480355:chitosan sulfate; D004247:DNA; D048271:Chitosan; D004996:Ethidium