Low-resolution structure of the full-length barley (Hordeum vulgare) SGT1 protein in solution, obtained using small-angle X-ray scattering.
SGT1 is an evolutionarily conserved eukaryotic protein involved in many important cellular processes. In plants, SGT1 is involved in resistance to disease. In a low ionic strength environment, the SGT1 protein tends to form dimers. The protein consists of three structurally independent domains (the tetratricopeptide repeats domain (TPR), the CHORD- and SGT1-containing domain (CS), and the SGT1-specific domain (SGS)), and two less conserved variable regions (VR1 and VR2). In the present study, we provide the low-resolution structure of the barley (Hordeum vulgare) SGT1 protein in solution and its dimer/monomer equilibrium using small-angle scattering of synchrotron radiation, ab-initio modeling and circular dichroism spectroscopy. The multivariate curve resolution least-square method (MCR-ALS) was applied to separate the scattering data of the monomeric and dimeric species from a complex mixture. The models of the barley SGT1 dimer and monomer were formulated using rigid body modeling with ab-initio structure prediction. Both oligomeric forms of barley SGT1 have elongated shapes with unfolded inter-domain regions. Circular dichroism spectroscopy confirmed that the barley SGT1 protein had a modular architecture, with an α-helical TPR domain, a β-sheet sandwich CS domain, and a disordered SGS domain separated by VR1 and VR2 regions. Using molecular docking and ab-initio protein structure prediction, a model of dimerization of the TPR domains was proposed.
Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Poznań, Poland.
Michał
M
Taube
Department of Cell Biology, Institute of Experimental BiFology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland.
Joanna R
JR
Pieńkowska
Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznań, Poland.
Artur
A
Jarmołowski
Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Poznań, Poland.
Maciej
M
Kozak
D000595:Amino Acid Sequence; D001467:Hordeum / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry*; D011487:Protein Conformation; D055503:Protein Multimerization; D053838:Scattering, Small Angle; D016415:Sequence Alignment; D014961:X-Ray Diffraction
D010940:Plant Proteins