Anomalous Laterally Stressed Kinetically Trapped DNA Surface Conformations  

作　　者：Valery V.Prokhorov Nikolay A.Barinov Kirill A.Prusakov Evgeniy V.Dubrovin Maxim D.Frank-Kamenetskii Dmitry V.Klinov 

机构地区：[1]Federal Research and Clinical Center of Physical-Chemical Medicine,Malaya Pirogovskaya,1a,Moscow 119435,Russian Federation [2]A.N.Frumkin Institute of Physical Chemistry and Electrochemistry,RAS,Leninsky prospect [3]Moscow 199071,Russian Federation 3 Moscow Institute of Physics and Technology,Institutskiy per.9,Dolgoprudny,141700 Moscow,Russian Federation [4]Lomonosov Moscow State University,Leninskie gory,1-2,Moscow 119991,Russian Federation [5]Department of Biomedical Engineering,Boston University,44 Cummington Mall,Boston MA02215,USA

出　　处：《Nano-Micro Letters》2021年第8期263-280,共18页纳微快报（英文版）

基　　金：This work was supported in part by a grant from Russian Scientific Foundation(Project No.17-75-30064).

摘　　要：Up to now,the DNA molecule adsorbed on a surface was believed to always preserve its native structure.This belief implies a negligible contribution of lateral surface forces during and after DNA adsorption although their impact has never been elucidated.High-resolution atomic force microscopy was used to observe that stiff DNA molecules kinetically trapped on monomolecular films comprising one-dimensional periodically charged lamellar templates as a single layer or as a sublayer are oversaturated by sharp discontinuous kinks and can also be locally melted and supercoiled.We argue that kink/anti-kink pairs are induced by an overcritical lateral bending stress(>30 pNnm)inevitable for the highly anisotropic 1D-1D electrostatic interaction of DNA and underlying rows of positive surface charges.In addition,the unexpected kink-inducing mechanical instability in the shape of the template-directed DNA confined between the positively charged lamellar sides is observed indicating the strong impact of helicity.The previously reported anomalously low values of the persistence length of the surface-adsorbed DNA are explained by the impact of the surface-induced low-scale bending.The sites of the local melting and supercoiling are convincingly introduced as other lateral stress-induced structural DNA anomalies by establishing a link with DNA high-force mechanics.The results open up the study in the completely unexplored area of the principally anomalous kinetically trapped DNA surface conformations in which the DNA local mechanical response to the surface-induced spatially modulated lateral electrostatic stress is essentially nonlinear.The underlying rich and complex in-plane nonlinear physics acts at the nanoscale beyond the scope of applicability of the worm-like chain approximation.

关 键 词：DNA surface conformations Kinetic trapping Lateral stress Periodically charged surface DNA kinks 

分 类 号：Q523[生物学—生物化学]