University of Oulu

Raasakka, A., Kursula, P. Stability and flexibility of full-length human oligodendrocytic QKI6. BMC Res Notes 12, 609 (2019).

Stability and flexibility of full-length human oligodendrocytic QKI6

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Author: Raasakka, Arne1,2; Kursula, Petri1,2
Organizations: 1Department of Biomedicine, Faculty of Medicine, University of Bergen, Bergen, Norway
2Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.6 MB)
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Language: English
Published: Springer Nature, 2019
Publish Date: 2020-03-13


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.

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Series: BMC research notes
ISSN: 1756-0500
ISSN-E: 1756-0500
ISSN-L: 1756-0500
Volume: 12
Article number: 609
DOI: 10.1186/s13104-019-4629-x
Type of Publication: A1 Journal article – refereed
Field of Science: 1182 Biochemistry, cell and molecular biology
3111 Biomedicine
Funding: This work was financially supported by the Sigrid Jusélius Foundation, the Emil Aaltonen Foundation, and the Department of Biochemistry, University of Oulu.
Copyright information: © The Author(s) 2019. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.