Evidence for similar structural organization of the multienzyme aminoacyl-tRNA synthetase complex in vivo and in vitro.
Although aminoacyl-tRNA synthetases from higher eukaryotic cells are routinely isolated as components of a multienzyme complex, it has remained unclear how closely the isolated complex reflects a structure that exists within the cell. To answer this question, we have used chemical cross-linking and immunological detection to identify the nearest neighbor(s) of arginyl-tRNA synthetase both in the isolated, purified complex and in saponin-permeabilized cells, which retain much of the structural organization of intact cells. Our results show that arginyl-tRNA synthetase is cross-linked primarily both in vitro and in vivo to a single protein, an as yet uncharacterized 38-kDa polypeptide known to be present in synthetase complexes from many sources. These data demonstrate that the isolated, multienzyme amino-acyl-tRNA synthetase complex reflects a defined structure that also pre-exists in the cell and that the 38-kDa polypeptide is an integral component of this complex.
Department of Biochemistry, University of Connecticut Health Center, Farmington 06032.
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Filonenko
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Deutscher
D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D002478:Cells, Cultured; D003432:Cross-Linking Reagents; D007668:Kidney / Q000201:enzymology; D011233:Precipitin Tests; D011487:Protein Conformation; D011817:Rabbits
D000911:Antibodies, Monoclonal; D003432:Cross-Linking Reagents; D000604:Amino Acyl-tRNA Synthetases