NONCOVALENT PROTEIN ASSEMBLY

The aminoacyl-tRNA synthetases are diverse proteins which offer a uniq ue opportunity to investigate protein assembly and evolution. Non-cova lent assembly of tRNA synthetases has been achieved by association of the core acceptor-stem binding catalytic domain with a domain that fac ilitates interactions with more distal parts of the tRNA molecule. The core catalytic domain has also been dissected into pieces which can b e reassembled through complementary chain-packing interactions. Curren t evidence suggests the possibility of assemblages of polypeptides as intermediates in the early development of long single-chain aminoacyl- tRNA synthetases.