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Stability and flexibility of full-length human oligodendrocytic QKI6

Authors :
Arne Raasakka
Petri Kursula
Source :
BMC Research Notes, Vol 12, Iss 1, Pp 1-7 (2019)
Publication Year :
2019
Publisher :
BMC, 2019.

Abstract

Abstract Objective Oligodendrocytes account for myelination in the central nervous system. During myelin compaction, key proteins are translated in the vicinity of the myelin membrane, requiring targeted mRNA transport. Quaking isoform 6 (QKI6) is a STAR domain-containing RNA transport protein, which binds a conserved motif in the 3′-UTR of certain mRNAs, affecting the translation of myelination-involved proteins. RNA binding has been earlier structurally characterized, but information about full-length QKI6 conformation is lacking. Based on known domains and structure predicitons, we expected full-length QKI6 to be flexible and carry disordered regions. Hence, we carried out biophysical and structural characterization of human QKI6. Results We expressed and purified full-length QKI6 and characterized it using mass spectrometry, light scattering, small-angle X-ray scattering, and circular dichroism spectroscopy. QKI6 was monodisperse, folded, and mostly dimeric, being oxidation-sensitive. The C-terminal tail was intrinsically disordered, as predicted. In the absence of RNA, the RNA-binding subdomain is likely to present major flexibility. In thermal stability assays, a double sequential unfolding behaviour was observed in the presence of phosphate, which may interact with the RNA-binding domain. The results confirm the flexibility and partial disorder of QKI6, which may be functionally relevant.

Details

Language :
English
ISSN :
17560500
Volume :
12
Issue :
1
Database :
Directory of Open Access Journals
Journal :
BMC Research Notes
Publication Type :
Academic Journal
Accession number :
edsdoj.8ac719f7dc3f47348d1c1f8c7c017c87
Document Type :
article
Full Text :
https://doi.org/10.1186/s13104-019-4629-x