Role of dimerization in yeast aspartyl-tRNA synthetase and importance of the class II invariant proline.
- 15 November 1993
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 90 (22), 10816-10820
- https://doi.org/10.1073/pnas.90.22.10816
Abstract
Cytoplasmic aspartyl-tRNA synthetase (AspRS; EC 6.1.1.12) from yeast is, as are most class II synthetases, an alpha 2 dimer. The only invariant amino acid in signature motif 1 of this class is Pro-273; this residue is located at the dimer interface. To understand the role of Pro-273 in the conserved dimeric configuration, we tested the effect of a Pro-273-->Gly (P273G) substitution on the catalytic properties of homo- and heterodimeric AspRS. Heterodimers of AspRS were produced in vivo by overexpression of their respective subunit variants from plasmid-encoded genes and purified to homogeneity in one HPLC step. The homodimer containing the P273G shows an 80% inactivation of the enzyme and an affinity decrease for its cognate tRNA(Asp) of one order of magnitude. The P273G-mutated subunit recovered wild-type enzymatic properties when associated with a native subunit or a monomer otherwise inactivated having an intact dimeric interface domain. These results, which can be explained by the crystal structure of the native enzyme complexed with its substrates, confirm the structural importance of Pro-273 for dimerization and clearly establish the functional interdependence of the AspRS subunits. More generally, the dimeric conformation may be a structural prerequisite for the activity of mononucleotide binding sites constructed from antiparallel beta strands.Keywords
This publication has 23 references indexed in Scilit:
- Cytoplasmic aspartyl‐tRNA synthetase from Saccharomyces cerevisiaeEuropean Journal of Biochemistry, 1991
- Partition of tRNA synthetases into two classes based on mutually exclusive sets of sequence motifsNature, 1990
- Study of the arrangement of the functional domains along the yeast cytoplasmic aspartyl‐tRNA synthetaseEuropean Journal of Biochemistry, 1989
- A high resolution diffracting crystal form of the complex between yeast tRNAAsp and aspartyl-tRNA synthetaseJournal of Molecular Biology, 1988
- Properties of N‐terminal truncated yeast aspartyl‐tRNA synthetase and structural characteristics of the cleaved domainEuropean Journal of Biochemistry, 1988
- The complete amino acid sequence of cytoplasmic aspartyl-tRNA synthetase from Saccharomyces cerevisiaeBiochimie, 1985
- Large scale purification and structural properties of yeast aspartyl-tRNA synthetaseBiochemical and Biophysical Research Communications, 1983
- Formation of a catalytically active complex between tRNAAsp and aspartyl-tRNA synthetase from yeast in high concentrations of ammonium sulphateBiochimie, 1982
- Crystallographic studies on the aspartyl-tRNA synthetase-tRNAAsp system from yeast: The crystalline aminoacyl-tRNA synthetaseJournal of Molecular Biology, 1980
- The subunit structure of methionyl‐tRNA synthetase from Escherichia coliFEBS Letters, 1974