AbstractThe three‐dimensional structure of the GroES monomer and its interaction with GroEL has been predicted using a combination of prediction tools and experimental data obtained by biophysical [electron microscope (EM), Fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR)] and biochemical techniques. The GroES monomer, according to the prediction, is composed of eight β‐strands forming a β‐barrel with loose ends. In the model, β‐strands 5–8 run along the outer surface of GroES, forming an antiparallel β‐sheet with β4 loosely bound to one of the edges. β‐strands 1–3 would then be parallel and placed in the interior of the molecule. Loops 1–3 would face the internal cavity of the GroEL–GroES complex, and together with conserved residues in loops 5 and 7, would form the active surface interacting with GroEL. © 1995 Wiley‐Liss, Inc.