Heckl W M, Smith D P, Binnig G, Klagges H, Hänsch T W, Maddocks J
Universität München, Section Physik, FRG.
Proc Natl Acad Sci U S A. 1991 Sep 15;88(18):8003-5. doi: 10.1073/pnas.88.18.8003.
Guanine, one of the four DNA bases, has been observed by tunneling microscopy to form a two-dimensional ordered structure on two crystalline substrates, graphite and MoS2. The two-dimensional lattice formed by guanine is nearly identical on the two surfaces, and heteroepitaxy appears to be the growth mechanism in both cases. Although the resolution of molecular details is superior for the graphite substrate, the simpler results on MoS2 are not only easier to interpret but also facilitate the understanding of the more complex images on graphite. We propose that the interfacial structure is composed of linear chains of hydrogen-bonded molecules aligned into a closely packed two-dimensional array.
