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Yeast tRNAAsp-aspartyl-tRNA synthetase: the crystalline complex
- Source :
- Journal of biomolecular structuredynamics. 1(1)
- Publication Year :
- 1983
-
Abstract
- Aspartyl-tRNA synthetase from yeast, a dimer of molecular weight 125,000 and its cognate tRNA (Mr = 24,160) were co-crystallized using ammonium sulfate as precipitant agent. The presence in the crystals of both components in the two-to-one stoichiometric ratio was demonstrated by electrophoresis, biological activity assays and crystallographic data. Crystals belong to the cubic space group I432 with cell parameter of 354 A and one complex particle per asymmetric unit. The solvent content of about 78% is favorable for a low resolution structural investigation. By exchanging H2O for D2O in mother liquors, advantage can be taken from contrast variation techniques with neutron radiations. Diffraction data to 20 A resolution were measured at five different contrasts, two of them being close to the theoretical matching point of RNA and protein in the presence of ammonium sulfate. The experimental extinction of the diffracted signal was observed to be close to 36% D2O, significantly different from the predicted value of 41%. The phenomenon can be explained by the existence of a large interface region between the two tRNAs and the enzyme. These parts of the molecules are hidden from the solvent and their protons are less easily exchangeable. Accessibility studies toward chemicals of tRNAAsp in solution and in the presence of synthetase are in agreement with such a model.
- Subjects :
- Models, Molecular
Ammonium sulfate
Stereochemistry
Protein Conformation
Dimer
Aspartate-tRNA Ligase
Molecular Sequence Data
Saccharomyces cerevisiae
Amino Acyl-tRNA Synthetases
chemistry.chemical_compound
Structural Biology
Molecular Biology
RNA, Transfer, Asp
Binding Sites
Base Sequence
Molecular Structure
Resolution (electron density)
RNA
General Medicine
RNA, Transfer, Amino Acid-Specific
Yeast
Solvent
Crystallography
Electrophoresis
chemistry
Transfer RNA
Nucleic Acid Conformation
Crystallization
Subjects
Details
- ISSN :
- 07391102
- Volume :
- 1
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Journal of biomolecular structuredynamics
- Accession number :
- edsair.doi.dedup.....4d16cc88892123d6e8eb99ff9dc86e6a