E0208

The Effects of ATP and Temperature on the Aggregation of GroEL in Solution. K.C. Littrell^[dagger], E. Quaite-Randall^#, P. Thiyagarajan^[dagger], and A. Joachimiak^#, ^[dagger]Intense Pulsed Neutron Source, ^#Center for Mechanistic Biology and Biotechnology, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA

Small-angle scattering studies of the Escheria coli GroEL chaperonin were carried out at several different temperatures with different concentrations of ATP. These studies reveal that the double-ring structure of GroEL is stable up to 55 ºC. The tetradecamer stucture begins to break down at 65 ºC, and at 75 ºC GroEL denatures, precipitating out of solution. We have investigated the thermal stability and aggregation states of GroEL complexes in the TT, TR, and RR states that are known to form at different ATP concentrations in solution. Details of these studies will be discussed.

Work supported by U.S. Department of Energy, BES, contract No. W-31-109-ENG-38.