Scanning tunneling microscopy on biological matter

We present scanning tunneling microscopy images for bare and shadowed recA-DNA complexes prepared on graphite substrates. Images of bare material can be associated with fragments of recA-DNA filaments and with a DNA molecule. On freeze-dried shadowed samples, fine structures on a cluster of parallel-arranged recA-DNA filaments could be attributed to recA monomers, single filaments on the other hand appeared structureless. © 1987.