Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 Singapore, Laboratory of Physical Chemistry and Colloid Science, Wageningen University, 6703 HB Wageningen, The Netherlands, Food and Biobased Research, Wageningen University, 6700 AA Wageningen, The Netherlands, BioSystems and Micromechanics (BioSym) IRG, Singapore MIT Alliance for Research and Technology (SMART), 117576 Singapore and Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Nucleic Acids Res. 2013 Nov;41(20):e189. doi: 10.1093/nar/gkt783. Epub 2013 Sep 3.
The effect of a cationic-neutral diblock polypeptide on the conformation of single DNA molecules confined in rectangular nanochannels is investigated with fluorescence microscopy. An enhanced stretch along the channel is observed with increased binding of the cationic block of the polypeptide to DNA. A maximum stretch of 85% of the contour length can be achieved inside a channel with a cross-sectional diameter of 200 nm and at a 2-fold excess of polypeptide with respect to DNA charge. With site-specific fluorescence labelling, it is demonstrated that this maximum stretch is sufficient to map large-scale genomic organization. Monte Carlo computer simulation shows that the amplification of the stretch inside the nanochannels is owing to an increase in bending rigidity and thickness of bottlebrush-coated DNA. The persistence lengths and widths deduced from the nanochannel data agree with what has been estimated from the analysis of atomic force microscopy images of dried complexes on silica.
利用荧光显微镜研究了在矩形纳米通道中受限的单链 DNA 分子的构象受到阳离子-中性二嵌段多肽的影响。随着多肽的阳离子部分与 DNA 的结合增加，观察到沿通道的伸展增强。在横截面直径为 200nm 的通道中，当多肽相对于 DNA 电荷的过量为 2 倍时，可以实现 85%的轮廓长度的最大伸展。通过定点荧光标记，证明这种最大伸展足以绘制大规模基因组组织。蒙特卡罗计算机模拟表明，纳米通道内伸展的放大是由于增加了梳状 DNA 的弯曲刚性和厚度。从纳米通道数据推断出的持久长度和宽度与从二氧化硅上干燥复合物的原子力显微镜图像分析中估计的值一致。
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