Scanning tunnelling microscopy (STM), which can provide 'direct' and 'non-a
veraged' information on molecular structure in three dimensions, has been u
sed to achieve sub-molecular resolution in a 'single molecule' of rubredoxi
n, an important iron-sulphur protein, at the gold (1 1 1) \ water interface
. The metal-ligand site [Fe (III)-Cys(4)] appears distinct because of an en
hancement of the tunnelling current over this region compared to the surrou
nding protein structure. (C) 2000 Elsevier Science Inc. All rights reserved
.