TITLE:
Helical Repeats of Left-Handed DNA
AUTHORS:
Youcheng Xu
KEYWORDS:
Left-Handed DNA, Ambidextrous Double Helix, Linking Number, Positive Supercoiling, Hyperthermophiles
JOURNAL NAME:
Open Journal of Molecular and Integrative Physiology,
Vol.4 No.2,
May
16,
2014
ABSTRACT: 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.