We applied scanning tunneling microscopy (STM) to the observation of amino acids and proteins deposited and/or adsorbed on highly oriented pyrolytic graphite (HOPG).
Although many questions remain, it is demonstrated that relatively high resolution images of uncoated proteins can often be obtained in air. We present images of five amino acids (glycine, leucine, lysine, methionine and tryptophan) and three proteins (lysozyme, albumin and fibrinogen) under various conditions of deposition and adsorption. We discuss the role of affinity of the amino acids and proteins to the substrate, their adsorbed states and distribution, and STM tip-induced deformation and/or destruction.
STM studies of adsorbed proteins are expected to provide useful and even unique information on the conformation and packing of the proteins.
Feng, L.; Andrade, J. D.; and Hu, C. Z.
"Scanning Tunneling Microscopy of Proteins on Graphite Surfaces,"
Scanning Microscopy: Vol. 3
, Article 1.
Available at: https://digitalcommons.usu.edu/microscopy/vol3/iss2/1