[Dynamic atomic force microscopic observation of the three-dimensional conformation of protein A-gold single molecule].
OBJECTIVE
To determine the three-dimensional (3D) conformation of staphylococcal protein A-gold (SPA-G) single molecule using atomic force microscope (AFM) so as to evaluate the feasibility of using this molecule for in situ labeling of the neuronal membrane protein.


METHODS
AFM was used to acquire the images of SPA-G binding to the surface of mica under physiological condition for determining the 3D conformation of the molecule.


RESULTS
SPA-G single molecule was shown to contain a characteristic structure with a chain in the shape of mirror image of the letter C, which had the dimension of 48.80 nm x 42.13 nm x 20.53 nm.


CONCLUSIONS
AFM provide a new means for morphological investigation of the biomacromolecule at the nanometer scale in physiological conditions, and SPA-G can be utilized for in situ labeling of the neuronal membrane receptors.
Yu
Yi-Gang
YG
Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China. yu-yg@tom.com
Xu
Ru-Xiang
RX
Cai
Ying-Qian
YQ
Jiang
Xiao-Dan
XD
Ke
Yi-Quan
YQ
D017979:Gold Colloid / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D008968:Molecular Conformation; D016194:Receptors, N-Methyl-D-Aspartate / Q000737:chemistry; D013205:Staphylococcal Protein A / Q000737:chemistry*
D017979:Gold Colloid; D016194:Receptors, N-Methyl-D-Aspartate; D013205:Staphylococcal Protein A