Cationic graft copolymer as a DNA B-z transition inducer: effect of copolymer structure.
The biological importance of left-handed Z-DNA was supported by the identification of Z-DNA binding proteins. We previously reported that poly(l-lysine)-graft-dextran copolymers composed of a poly(l-lysine) main chain and dextran graft chains induced the B-Z transition under low salt conditions. Not only the cationic main chain but also the dextran grafts play an important role in induction of the B-Z transition. In this study, we prepared a series of poly(l-lysine) graft copolymers with different graft chains (dextran, poly(ethylene glycol) (PEG), or both) and graft contents to further elucidate the roles of copolymer structures and properties. The copolymers with higher graft contents more effectively stabilized the Z form of DNA than those having lower graft contents. An increase in the B-Z transition rate was observed as graft content increased. We propose that the side chains of the copolymers change microenvironmental factors, such as water activity and dielectric constant, around the DNA and stabilize the Z conformer. Interestingly, hetero graft copolymers with both dextran and PEG side chains stabilized Z-DNA more effectively than the homo graft copolymers with either dextran or PEG side chains.
Shimada
Naohiko
N
Institute for Materials Chemistry and Engineering, Kyushu University, Motooka 744-CE11, Nishi-ku, Fukuoka 819-0395, Japan, and CREST, Japan Science and Technology Agency, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075, Japan.
Yamamoto
Miyuki
M
Kano
Arihiro
A
Maruyama
Atsushi
A
D002412:Cations / Q000737:chemistry; D043542:DNA, Z-Form / Q000737:chemistry*; D003911:Dextrans / Q000138:chemical synthesis / Q000737:chemistry*; D007700:Kinetics; D015394:Molecular Structure; D011107:Polylysine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry
D002412:Cations; D043542:DNA, Z-Form; D003911:Dextrans; C113090:poly(lysine)-graft-dextran; D011107:Polylysine