Helical Repeats of Left-Handed DNA

• 作者: Youcheng Xu
• 来源期刊: 分子和综合生理学期刊(英文)
• 学科: 医学
• 关键词: LEFT-HANDED DNA Ambidextrous Double HELIX Linking Number Positive SUPERCOILING HYPERTHERMOPHILES
• 年，卷（期）: 2014,（2）
• 页码范围: 20-26
• 页数: 7页
• 分类号: R73

摘要

DNA is generally assumed as a right-handed double helix and Z-DNA is a special kind of left-handed DNA infrequently found in nature. However, the finding of a zero linking number topoisomer supports a hypothesis that the two strands of DNA are winding ambidextrously, rather than plectonemically. It logically leads to a notion that the left-handed DNA is as common as right-handed DNA and the amount of left-handed DNA in a positively supercoiled plasmid prevails that of the right-handed DNA. In this report, the helical repeat of left-handed DNA, 12 bp per turn, was determined by a new method. How the positively supercoiled DNA was generated in hyperthermophiles and why their DNA can withstand the extreme high temperature are answered from an alternative theory.