https://mmbr.asm.org/content/mmbr/33/2/264.full.pdf

Mechanism of protein biosynthesis.

Fluorescence studies of interactions between Escherichia coli valyl-tRNA synthetase and its substrates☆

Publisher Summary The aminoacyl-tRNA synthetases are a family of enzymes that play a key role in protein biosynthesis This chapter discusses the molecular and catalytic properties of aminoacyl-tRNA synthetases It also discusses the genetics and regulation of aminoacyl-tRNA synthetases In procaryotes they are contained in the nonsedimentable supernatant of cell extracts In eucaryotic organisms, aminoacyl-tRNA synthetases are found in the organelles, and in many cases these differ from the corresponding cytoplasmic enzymes The latter may not exist in a “free state” in the cytoplasm In mammalian cells, for instance, large, fast sedimenting complexes have been found, which contain some or all aminoacyl-tRNA synthetases together with tRNA or other parts of the protein synthesizing machinery The occurrence of some aminoacyl-tRNA synthetases in mammalian viruses has also recently been reported In eucaryotic organisms, aminoacyl-tRNA synthetases different from those found in the cytoplasm are contained in organelles as part of their separate protein synthesizing machinery In mitochondria, some of these enzymes are specific for mitochondrial tRNA's and will not aminoacylate tRNA from the cytoplasm of the same organism To date these enzymes are little characterized, and it is not known whether specific aminoacyl-tRNA synthetases for all 20 amino acids are present in the mitochondrion

15. Aminoacyl-tRNA Synthetases

Studies on valyl-tRNA synthetase and tRNA from Escherichia coli. I. Purification and properties of the enzyme from normal Escherichia coli strains.

Molecular weights of 18 aminoacyl-tRNA-synthetases of E. coli were estimated by gel filtration on Sephadex G-200. Molecular weights calculated from S20 and D20 values are known for four of the aminoacyl-tRNA-synthetases, the phenylalanyl- (Stulberg, 1967), isoleucyl- (Baldwin and Berg, 1966), tyrosyl- (Calendar and Berg, 1966) and the arginyl-tRNA-synthetase (Stoffler and Nass, 1967). These enzymes have been used as marker proteins for determination of the molecular weights of further 14 aminoacyl-tRNA-synthetases:
 The reliability of the used gel filtration for molecular weight determination is discussed.

W. Seifert

Papers

Electrophoretic separation of tRNA-bound leucyl-tRNA synthetase from Escherichia coli extracts