Life Sciences Nanotheater

Protein GroES

AFM provides true angstrom-level molecular topography of uncoated, unstained samples under physiologic buffer. Here, the structure of GroES, a heptameric protein (monomer, 10 kDa) which functions in the cell's protein folding machinery, is imaged under buffer by AFM to a lateral resolution of 10 Å and a vertical resolution of 1 Å. GroES is a member of the chaperonin 10 family of proteins. Distinct heptameric "crown" structures (lighter yellow areas) 45 Å in diameter protruding 8 Å above the outer GroES surface (84 Å in diameter) were recently confirmed by x-ray crystallography. Such topographic information on single molecules is unavailable using other microscopic methods (e.g., electron microscopy). 78.3nm scan size. Used by permission: see Mou et al., (1996) FEBS Lett. 381: 161-164.