Characterization of postribosomal aminoacyl-tRNA synthetases in cultured Chinese hamster ovary cells.

摘要: Abstract Postribosomal aminoacyl-tRNA synthetases from cultured Chinese hamster ovary cells are found in forms of defined size. Sedimentation distribution profiles on calibrated 10–30% (w/v) exponential sucrose gradients two different buffer systems show that the number and nature synthetase complexes vary a manner. Synthetases sediment three general size classes B (10 mM KCl, 10 Tris-HCl (pH 7.4 at 25°C), 1.0 MgCl 2 0.1 dithiothreitol) gradients. Alanyl-, asparaginyl-, seryl-, tryptophanyl- tyrosyl-tRNA have single activity peak sediments 6–10 S; cysteinyl-, histidyl-, phenylalanyl- valyl-tRNA 15–21 S form plus an 8–10 form; aspartyl-, arginyl-, glutaminyl-, glutamyl-, isoleucyl-, leucyl-, lysyl-, methionyl-, prolyl- threonyl-tRNA 30 plus, some cases, one or more slower sedimenting forms. In A (same as except containing 100 KCl 1.5 ), alanyl-, tryptophanyl-tRNA very similar those Arginyl-, prolyl-, threonyl-, tyrosyl-, similarly shaped both systems, but appear to shift slightly sedimentation rate A. Aspartyl-, phenylalanyl-tRNA differ quite markedly providing evidence all separate complexes. The distributions compared with total RNA protein postribosomal particles. Observations discussed terms exist.