ANALYSIS AND CRYSTALLIZATION OF A 25 KDA C-TERMINAL FRAGMENT OF CLONED ELONGATION-FACTOR-TS FROM ESCHERICHIA-COLI

A 25 kDa C-terminal tryptic fragment of elongation factor Ts has been purified to homogeneity, Experimental evidence suggests that the 25 kD a C-terminal and the 5.3 kDa N-terminal fragments are structurally ind ependent domains. The N-terminal fragment is shown to be essential for the nucleotide exchange activity. Crystals of the C-terminal fragment belong to space group P2 or P2(1), The diffraction pattern shows a pr onounced pseudo-C2 symmetry at low resolution. This pseudo symmetry in creases when the crystals are irradiated with X-rays for a few hours.