title: Naturally occurring branched-chain polyamines induce a crosslinked meshwork structure in a giant DNA.
abstract: We studied the effect of branched-chain polyamines on the folding transition of genome-sized DNA molecules in aqueous solution by the use of single-molecule observation with fluorescence microcopy. Detailed morphological features of polyamine/DNA complexes were characterized by atomic force microscopy (AFM). The AFM observations indicated that branched-chain polyamines tend to induce a characteristic change in the higher-order structure of DNA by forming bridges or crosslinks between the segments of a DNA molecule. In contrast, natural linear-chain polyamines cause a parallel alignment between DNA segments. Circular dichroism measurements revealed that branched-chain polyamines induce the A-form in the secondary structure of DNA, while linear-chain polyamines have only a minimum effect. This large difference in the effects of branched- and linear-chain polyamines is discussed in relation to the difference in the manner of binding of these polyamines to negatively charged double-stranded DNA.
authors.affiliation: Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe 610-0394, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Muramatsu
authors.affiliation: Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe 610-0394, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe 610-0394, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yoshikawa
authors.affiliation: College of Life Sciences, Ritsumeikan University, Kusatsu 525-8577, Japan.
authors.forename: Wakao
authors.initials: W
authors.lastname: Fukuda
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Umezawa
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan.
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Horai
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan.
authors.forename: Tsunehiko
authors.initials: T
authors.lastname: Higuchi
authors.affiliation: School of Science and Technology, Kwansei-Gakuin University, Sanda 669-1337, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Fujiwara
authors.affiliation: College of Life Sciences, Ritsumeikan University, Kusatsu 525-8577, Japan.
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Imanaka
authors.affiliation: Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe 610-0394, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Yoshikawa
mesh_terms: D000818:Animals; D017122:Bacteriophage T4; D002417:Cattle; D002942:Circular Dichroism; D003432:Cross-Linking Reagents / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004279:DNA, Viral / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D015394:Molecular Structure; D011073:Polyamines / Q000737:chemistry*
chemical_list: D003432:Cross-Linking Reagents; D004279:DNA, Viral; D011073:Polyamines; D004247:DNA; C427203:calf thymus DNA