An improved sample preparation procedure and optimized atomic force microscope (AFM) imaging conditions that makes it possible to obtain reproducible nanometer resolution AFM images of plasmid DNA with nanograms of the sample is presented. The Bst DNA polymerase I is a special kind of DNA polymerase that can keep its function even at high temperature (approximately 65-degrees-C), but little is known about its surface structure. The AFM images of the Bst DNA polymerase I show its special surface structure.