Allen M J, Balooch M, Subbiah S, Tench R J, Siekhaus W, Balhorn R
Biomedical Sciences, Lawrence Livermore National Laboratory, CA 94550.
Scanning Microsc. 1991 Sep;5(3):625-30.
The scanning tunneling microscope has been used to obtain images of DNA that reveal its major and minor grooves and the direction of helical coiling, but sufficient resolution has not yet been achieved to identify its bases. To determine if this technology is capable of identifying individual DNA bases, we have examined the molecular arrangements of adenine and thymine attached to the basal plane of highly oriented pyrolytic graphite. Both molecules form highly organized lattices following deposition on heated graphite. Lattice dimensions, structural periodicities, and the epitaxy of adenine and thymine molecules with respect to the basal plane of graphite have been determined. Images of these molecules at atomic resolution reveal that the aromatic regions are strongly detected in both molecules while the various side-groups are not well-resolved. These studies provide the first evidence that tunneling microscopy can be used to discriminate between purines and pyramidines.
扫描隧道显微镜已被用于获取DNA图像，这些图像揭示了其大沟和小沟以及螺旋卷曲的方向，但尚未达到足以识别其碱基的分辨率。为了确定这项技术是否能够识别单个DNA碱基，我们研究了附着在高度取向热解石墨基面上的腺嘌呤和胸腺嘧啶的分子排列。两种分子在沉积到加热的石墨上后都形成了高度有序的晶格。已经确定了晶格尺寸、结构周期性以及腺嘌呤和胸腺嘧啶分子相对于石墨基面的外延。这些分子的原子分辨率图像显示，在两种分子中都能强烈检测到芳香区域，而各种侧基则分辨率不佳。这些研究提供了首个证据，表明隧道显微镜可用于区分嘌呤和嘧啶。
