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Effect of Phosphorylation on a Human-like Osteopontin Peptide

Published

Author(s)

Samuel Lenton, Marco Grimaldo, Felix Roosen-Runge, Frank Schreiber, Tommy Nylander, Roger Clegg, Carl Holt, Michael Hartlein, Victoria Garcia Sakai, Tilo Seydel, Susana C. Marujo Teixeira

Abstract

Osteopontin is a disordered phosphoprotein that is expressed in many species and tissues and has a range of distinct functions. A notable property of more highly phosphorylated isoforms of osteopontin is their ability to sequester nanoclusters of calcium phosphate, to form a core-shell structure in a fluid that is supersaturated by stable. The effect is used in biology to allow soft and hard tissues to co-exist in the same organism with relative ease. Here, we extend our understanding of the effect of phosphorylation on the conformation and dynamics of intrinsically disordered proteins through a comparative study of an unphosphorylated and phosphorylated form of a recombinant human osteopontin mutant. The solution structures of the two forms were investigated by small-angle X-ray scattering to show that, within error, they have the same radii and maximum inter-atomic distance. The dynamics of the hydrated powders of the two rOPN peptides were investigated by elastic and quasi-elastic incoherent neutron scattering. Phosphorylation changed the dynamics on the nanosecond timescale but did not induce secondary structure or fluctuations on the picosecond time scale. The resilience of the peptide to the onset of diffusive motions was nearly independent of the state of phosphorylation can change the dynamic behaviour of even a highly disordered protein, with consequences for how it can interact with its substrates, cofactors, and, in the present case, amorphous or crystalline biominerals.
Citation
Biophysical Journal
Volume
112
Issue
8

Keywords

Intrinsically disordered proteins, Biomineralization, phosphorylation, quasi-elastic incoherent neutron scattering, small-angle scattering

Citation

Lenton, S. , Grimaldo, M. , Roosen-Runge, F. , Schreiber, F. , Nylander, T. , Clegg, R. , Holt, C. , Hartlein, M. , Sakai, V. , Seydel, T. and Marujo Teixeira, S. (2017), Effect of Phosphorylation on a Human-like Osteopontin Peptide, Biophysical Journal, [online], https://doi.org/10.1016/j.bpj.2017.03.005, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=922155 (Accessed October 24, 2021)
Created April 24, 2017, Updated October 12, 2021