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N o v e m b e r 2 3 - 2 4 , 2 0 1 8 | B a n g k o k , T h a i l a n d
Plant Science Congress 2018
Journal of Agricultural Science and Botany
ISSN: 2591-7897 | Volume 2
OF EXCELLENCE
IN INTERNATIONAL
MEETINGS
alliedacademies.comYEARS
PLANT GENOMICS
AND PLANT SCIENCE
World Congress on
J Agric Sci Bot 2018, Volume 2 | DOI: 10.4066/2591-7897-C2-006
THE CENTERS OF PREMELTONS SIGNAL THE BEGINNING AND ENDS OF
GENES
Henry M Sobell
University of Rochester, USA
P
remeltons are examples of emergent structures (i.e., structural solitons) that arise spontaneously in DNA due to the presence
of nonlinear excitations in its structure. They are of two kinds: B-B (or A-A) premeltons form at specific DNA-regions to nu-
cleate site-specific DNA melting. These are stationary and, being globally nontopological, undergo breather motions that allow
drugs and dyes to intercalate into DNA. B-A (or A-B) premeltons, on the other hand, are mobile, and being globally topological,
act as phase-boundaries transforming B-into A- DNA during the structural phase-transition. They are not expected to undergo
breather-motions. A key feature of both types of premeltons is the presence of an intermediate structural-form in their central
regions (proposed as being a transition-state intermediate in DNA-melting and in the B- to A- transition), which differs from either
A-or B- DNA. Called beta-DNA, this is both metastable and hyperflexible – and contains an alternating sugar-puckering pattern
along the polymer-backbone combined with the partial-unstacking (in its lower energy-forms) of every other base-pair. Beta-DNA
is connected to either B- or to A- DNA on either side by boundaries possessing a gradation of nonlinear structural-change, these
being called the kink and the antikink regions. The presence of premeltons in DNA leads to a unifying theory to understand much
of DNA physical-chemistry and molecular-biology. In particular, premeltons are predicted to define the 5’ and 3’ ends of genes in
naked-DNA and DNA in active-chromatin, this having important implications for understanding physical aspects of the initiation,
elongation and termination of RNA-synthesis during transcription. For these and other reasons, the model will be of broader
interest to the general audience working in these areas. The model explains a wide variety of data, and carries within it a number
of experimental predictions – all readily testable – as will be described in my talk.