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Brain Expressed X‐linked 3 (BEX3) is a High‐Order Oligomer with Partially Folded Regions
Author(s) -
Cabral Katia,
Raymundo Diana,
Silva Viviane,
Sampaio Laura,
Hill Luis Fernando,
Almeida Fabio,
Cordeiro Yraima,
Almeida Marcius
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.598.1
Subject(s) - oligomer , intrinsically disordered proteins , circular dichroism , chemistry , biophysics , crystallography , globular protein , neurodegeneration , small angle x ray scattering , nuclear magnetic resonance spectroscopy , intracellular , biology , biochemistry , stereochemistry , scattering , medicine , physics , disease , organic chemistry , pathology , optics
The members of the family of Brain Expressed X‐linked (BEX) are mammal‐specific proteins involved in neurodegeneration, cell cycle and cancer. However, very limited data are available on the conformational state of any member of the BEX family. Recently, BEX3 has been predicted to be intrinsically disordered and also to represent an intracellular hub for cell signaling. In this study, we characterized the BEX3 structure using biophysical experimental data. The association of atomic force microscopy and small angle X‐ray scattering revealed that BEX3 forms a specific higher‐order oligomer that is consistent with a globular molecule. The partial proteinase K digestion has suggested that BEX3 structure contains a core which is proteolysis‐resistant around residues 55–120 with unfolded regions at the N‐ and C‐termini. Circular dichroism spectroscopy and solution nuclear magnetic resonance data revealed that BEX3 exists in solution as an oligomer with partially disordered segments at the N‐ and C‐termini and with a more compact helical structure in a central core. The self‐oligomerization of BEX3 has been previously reported in cell culture and is consistent with our in vitro data. We speculate whether the self‐association of BEX3 into a folded core offers a natural mechanism to protect it from degradation and possibly even to regulate its activity. Support or Funding Information FAPERJ, CNPq, INBEB, CENABIO.