CONFORMATIONAL-CHANGES AND SPATIAL ARRANGEMENT OF THE ESCHERICHIA-COLI CHAPERONES GROEL AND GROES

We determined small-angle neutron-scattering (SANS) curves of isolated GroEL (R-G = (6.20 +/- 0.04) nm) and GroES (R-G = (3.07 +/- 0.01) nm) and showed that the obtained structural information is compatible wit h the data from X-ray crystallography. Our neutron scattering investig ations, along with molecular modeling, allowed us to propose the proba ble location of residues that were previously not resolved in the crys tallographic structure, Significant differences between isolated GroEL and GroES compared to the components in complex were revealed by the scattering curves. The center-to-center distance between GroEL and Gro ES in the complex (R-G = (6.35 +/- 0.02) nm and (2.99 +/- 0.02) nm, re spectively) was determined (d = 8.6 nm).