CRYSTAL-STRUCTURE OF ACTIVE ELONGATION-FACTOR TU REVEALS MAJOR DOMAINREARRANGEMENTS

The crystal structure of intact elongation factor Tu (EF-Tu) from Ther mus thermophilus has been determined and refined at an effective resol ution of 1.7 angstrom, with incorporation of data extending to 1.45 an gstrom. The effector region, including interaction sites for the ribos ome and for transfer RNA, is well defined. Molecular mechanisms are pr oposed for transduction and amplification of the signal induced by GTP binding as well as for the intrinsic and effector-enhanced GTPase act ivity of EF-Tu. Comparison of the structure with that of EF-Tu-GDP rev eals major mutual rearrangements of the three domains of the molecule.