PJB-2018-299
Structural characterization of 12S seed Cruciferin from Eruca sativa in solution applying small-angle X-ray scattering
Binish Khaliq, Sven Falke, Sadaf Iqbal, Friedrich Buck, Seema Mahmood, Zahid Ali, Maqsood Ahmad, Abdul Wahid Christian Betzel and Ahmed Akrem
Abstract
Cruciferin (12S globulin) from seeds of Eruca sativa was isolated, purified and thoroughly characterized. The protein indicated 54 % sequence identity with the cruciferins of Brassica napus (CRU1) and Raphanus sativus (PGCRURSE5) when the obtained amino acid sequence from LC-MS/MS mass spectrometric data was submitted to the UniProtKB. SDS-PAGE exhibited an approx. 50 kDa monomeric cruciferin, which was separated into α-polypeptide with a major band at approx. 30 kDa and a β-polypeptide of approx. 20 kDa under reduced conditions. The secondary structure content of E. sativa Cruciferin (EsC) was analyzed by Circular Dichroism spectroscopy indicating 7% α-helix, 48% β-sheet, 7% β-turn and 38% disordered conformation. The monodispersity and stability of EsC was verified via Dynamic Light Scattering (DLS) and a hydrodynamic radius of EsC was calculated to be 5.5 ± 0.3 nm indicating a trimer of the protein in solution. A gyration radius (Rg) of 4.3± 0.30 nm and the globular molecular shape was disclosed by Small-angle X-ray scattering (SAXS) for EsC. An incredibly analogous globular shape was obtained when the ab-initio dummy model of EsC inferring P3 symmetry was carefully compared with the PDB-ID 3KGL; 11S globulin of Brassica napus. Moreover, the scattering patterns of both proteins showed a minimized χ2-value of 2.0 which further confirms the structural similarities. Protruding loops of the EsC model were considered as hyper variable region-I (HVR-I) of Arabidopsis thaliana Cruciferin C (AtCruC) and variable region II of 3KGL molecular structure and were nominated as the major flexible regions.
To Cite this article:
Khaliq, B., S. Falke, S. Iqbal, F. Buck, S. Mahmood, Z. Ali, M. Ahmad and A. Wahid. 2019. Christian Betzel and Ahmed Akrem - Structural characterization of 12S seed Cruciferin from Eruca sativa in solution applying small-angle X-ray scattering. Pak. J. Bot., 51(4): DOI: http://dx.doi.org/10.30848/PJB2019-4(29)
Download
