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Updated: Feb 2, 2026

Pull-down of Calmodulin-binding Proteins
Published on: January 23, 2012
Purification, modeling and structural insights of calmodulin-binding receptor like cytoplasmic kinase 2 from Oroxylum
Nabeel Ali1, Mohd Amir1, Md Imtaiyaz Hassan1
1Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
Abstract:
Calmodulin binding receptor like cytoplasmic kinase 2 (CRCK2) belongs to the family of receptor like kinases (RLKs) which is mainly implicated in pathways associated with the stress responses in plants. The protein from the stem of Oroxylum indicum was isolated and purified using anion-exchange followed by gel filtration chromatography. The purity of protein was checked using SDS-PAGE, which showed a single band of 50 kDa. The purified protein was identified as CRCK2 using MALDI-TOF. Using I-TASSER, a bioinformatics tools, the model of protein was constructed and its secondary structure was predicted using VADAR. The secondary structure content was also determined by far-UV CD, which indicated that the CRCK2 is mainly β-sheet dominating protein (43% β-sheet). The secondary structural content predication from computational method is in close agreement with the result obtained by CD spectropolarimeter. This study validates I-TASSER model for determination of structure of a protein. Moreover, stability of CRCK2 was monitored against heat- and guanidinium chloride (GdmCl)-induced denaturation by using circular dichroism (CD) and fluorescence spectroscopy. Denaturation curve analysis gave values of 2.88 ± 0.12 kcal mol-1and 4.11 ± 0.09 M for ∆°GD (Gibbs free energy change at 25 °C) and Cm (midpoint of denaturation), respectively. It has been observed that purified CRCK2 is quite stable protein against both heat-induced as well as GdmCl-induced denaturation. This is very first report of purification and biophysical characterization of CRCK2 protein from medicinal plant O. indicum.
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