SOLUTION X-RAY-SCATTERING STUDY ON THE CHAPERONIN GROEL FROM ESCHERICHIA-COLI

The molecular architecture of native GroEL has been studied by solutio n X-ray scattering. The radius of gyration for the native molecule was estimated to be 66.0 Angstrom in 50 mM Tris-HCl, 100 mM KCI at pH 7.5 and 25 degrees C. The maximum dimension was estimated to be 170 Angst rom based on the pair distance distribution function. A cylindrical st ructure or two heptameric rings was found to be the best for native Gr oEL among structures examined by using a multi-sphere model analysis i n which the radius of constituent sphere was 6 Angstrom. The results o f the model analysis show that the radius of GroEL is 68.0 Angstrom an d the height is 150.7 Angstrom. Unexpectedly, the central penetrating hole through GroEL was not confirmed in the best-fit structure.