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Neurodegenerative disease-associated mutants of a human mitochondrial aminoacyl-tRNA synthetase present individual molecular signatures.

Sauter C, Lorber B, Gaudry A, Karim L, Schwenzer H, Wien F, Roblin P, Florentz C, Sissler M - Sci Rep (2015)

Bottom Line: The effects of these mutations on the structure and function of the enzymes remain to be established.Mutations with mild effects on solubility occur in patients as allelic combinations whereas those with strong effects on solubility or on aminoacylation are necessarily associated with a partially functional allele.The fact that all mutations show individual molecular and cellular signatures and affect amino acids only conserved in mammals, points towards an alternative function besides aminoacylation.

View Article: PubMed Central - PubMed

Affiliation: Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, IBMC, 15 rue René Descartes, 67084 STRASBOURG Cedex, France.

ABSTRACT
Mutations in human mitochondrial aminoacyl-tRNA synthetases are associated with a variety of neurodegenerative disorders. The effects of these mutations on the structure and function of the enzymes remain to be established. Here, we investigate six mutants of the aspartyl-tRNA synthetase correlated with leukoencephalopathies. Our integrated strategy, combining an ensemble of biochemical and biophysical approaches, reveals that mutants are diversely affected with respect to their solubility in cellular extracts and stability in solution, but not in architecture. Mutations with mild effects on solubility occur in patients as allelic combinations whereas those with strong effects on solubility or on aminoacylation are necessarily associated with a partially functional allele. The fact that all mutations show individual molecular and cellular signatures and affect amino acids only conserved in mammals, points towards an alternative function besides aminoacylation.

No MeSH data available.


Related in: MedlinePlus

Comparative size and secondary structure elements of WT and mutant mt-AspRSs.(A) Particle hydrodynamic diameter distribution by intensity as measured by DLS. (B) Concentration dependence of particle diameter of WT, Q184K and R263Q as determined by DLS. (C) Overlay of the SRCD spectra of WT and mutants at 24°C. Color code is the same in all panels, as indicated in panel (C).
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f2: Comparative size and secondary structure elements of WT and mutant mt-AspRSs.(A) Particle hydrodynamic diameter distribution by intensity as measured by DLS. (B) Concentration dependence of particle diameter of WT, Q184K and R263Q as determined by DLS. (C) Overlay of the SRCD spectra of WT and mutants at 24°C. Color code is the same in all panels, as indicated in panel (C).

Mentions: Particle size distributions by intensity derived from DLS measurements performed independently in two instruments indicated that WT and mutants had mean hydrodynamic diameters of dh = 10 ± 1 nm, except Q184K whose size was slightly greater (Fig. 2A and Supplementary Fig. 1). Concentration dependence analysis confirmed that the dh of this mutant was ~12 ± 1 nm after extrapolation to zero concentration (Fig. 2B). SLS analyses also showed that Q184K was distinguished from other samples by a ~20% higher mean molecular mass (results not shown). The content of secondary structure elements in all seven proteins was investigated by SRCD. Far-UV spectra indicated that all contain α-helices, ß-sheets and less structured regions in similar proportions (Fig. 2C, and Supplementary Fig. 2 and Table 2).


Neurodegenerative disease-associated mutants of a human mitochondrial aminoacyl-tRNA synthetase present individual molecular signatures.

Sauter C, Lorber B, Gaudry A, Karim L, Schwenzer H, Wien F, Roblin P, Florentz C, Sissler M - Sci Rep (2015)

Comparative size and secondary structure elements of WT and mutant mt-AspRSs.(A) Particle hydrodynamic diameter distribution by intensity as measured by DLS. (B) Concentration dependence of particle diameter of WT, Q184K and R263Q as determined by DLS. (C) Overlay of the SRCD spectra of WT and mutants at 24°C. Color code is the same in all panels, as indicated in panel (C).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664897&req=5

f2: Comparative size and secondary structure elements of WT and mutant mt-AspRSs.(A) Particle hydrodynamic diameter distribution by intensity as measured by DLS. (B) Concentration dependence of particle diameter of WT, Q184K and R263Q as determined by DLS. (C) Overlay of the SRCD spectra of WT and mutants at 24°C. Color code is the same in all panels, as indicated in panel (C).
Mentions: Particle size distributions by intensity derived from DLS measurements performed independently in two instruments indicated that WT and mutants had mean hydrodynamic diameters of dh = 10 ± 1 nm, except Q184K whose size was slightly greater (Fig. 2A and Supplementary Fig. 1). Concentration dependence analysis confirmed that the dh of this mutant was ~12 ± 1 nm after extrapolation to zero concentration (Fig. 2B). SLS analyses also showed that Q184K was distinguished from other samples by a ~20% higher mean molecular mass (results not shown). The content of secondary structure elements in all seven proteins was investigated by SRCD. Far-UV spectra indicated that all contain α-helices, ß-sheets and less structured regions in similar proportions (Fig. 2C, and Supplementary Fig. 2 and Table 2).

Bottom Line: The effects of these mutations on the structure and function of the enzymes remain to be established.Mutations with mild effects on solubility occur in patients as allelic combinations whereas those with strong effects on solubility or on aminoacylation are necessarily associated with a partially functional allele.The fact that all mutations show individual molecular and cellular signatures and affect amino acids only conserved in mammals, points towards an alternative function besides aminoacylation.

View Article: PubMed Central - PubMed

Affiliation: Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, IBMC, 15 rue René Descartes, 67084 STRASBOURG Cedex, France.

ABSTRACT
Mutations in human mitochondrial aminoacyl-tRNA synthetases are associated with a variety of neurodegenerative disorders. The effects of these mutations on the structure and function of the enzymes remain to be established. Here, we investigate six mutants of the aspartyl-tRNA synthetase correlated with leukoencephalopathies. Our integrated strategy, combining an ensemble of biochemical and biophysical approaches, reveals that mutants are diversely affected with respect to their solubility in cellular extracts and stability in solution, but not in architecture. Mutations with mild effects on solubility occur in patients as allelic combinations whereas those with strong effects on solubility or on aminoacylation are necessarily associated with a partially functional allele. The fact that all mutations show individual molecular and cellular signatures and affect amino acids only conserved in mammals, points towards an alternative function besides aminoacylation.

No MeSH data available.


Related in: MedlinePlus