Protein Structural Characterization by Scanning Tunneling Microscopy with Electrochemistry

The structure characterization of native and unfolded enzymes and redox proteins like hemoglobin(Hb), myoglobin(Mb), cytochrome c and beef liver catalase etc. by STM on an electrochemically prepared HOPG surface has been studied with the help of electrodeposition. The capability of electrochemical method to prepare stable Hb samples for STM image and for unfolding of this protein has been successfully developed. STM images show an oval-shaped pattern for the native structure of Hb and two dimers consisting of one Hb molecule is clearly discerned. The dimension of folded molecule is determined as 6.4×5.3×0.7 nm³.