Among twenty ARSs, eight ARSs (RARS, DARS, QARS, EPRS, LARS, IARS, KARS, and MARS) with three nonsynthetase components, aminoacyl tRNA synthetase complex-interaction multifunctional protein (AIMP) 1, 2 and 3, are known to form a supramolecular multi-tRNA synthetase complex (MSC), whose molecular weight has been proposed to be about 1.5 MDa.
Source: wiktionary