Title
Branched‐chain polyamine found in hyperthermophiles induces unique temperature‐dependent structural changes in genome‐size DNA
Author
Tkashi Nishio, Yuko Yoshikawa, Wakao Fukuda, Naoki Umezawa, Tsunehiko Higuchi, Shinsuke Fujiwara, Tadayuki Imanaka, Kenichi Yoshikawa
Year
2018
Journal
ChemPhysChem
Abstract
A pentavalent branched‐chain polyamine, N4‐bis(aminopropyl)spermidine [3(3)(3)4], is a unique polycation found in a hyperthermophilic archaeon Thermococcus kodakarensis that grows at temperatures between 60 and 100°C. We studied the effects of this branched‐chain polyamine on DNA structure at different temperatures up to 80°C. Atomic force microscopic observations showed that DNA molecules exhibit a shrunken conformation in the presence of 3(3)(3)4 at 24°C. With an increase in temperature, DNA molecules tend to unwind, and multiple nano‐loops with a diameter of 10 ‐ 50 nm are generated along the DNA strand at 80°C. These results were compared to those obtained with linear‐chain polyamines, homocaldopentamine [3334] and spermidine, the former of which is a structural isomer of 3(3)(3)4. The effects of the branched‐chain polyamine on the secondary and higher‐order structures of DNA are discussed in relation to the ability to stabilize DNA against thermal denaturation.
Instrument
J-720
Keywords
Circular dichroism, DNA structure, Thermal stability, Chemical stability, Biochemistry