title: Secretagogin, a hexa EF-hand calcium-binding protein: high level bacterial overexpression, one-step purification and properties.
abstract: Secretagogin (SCGN), a hexa EF-hand calcium-binding protein, is highly expressed in the endocrine cells (especially in pancreatic islets) and in restricted neuronal sub-populations, albeit at comparatively low level. Since SCGN is predicted to be a potential neuroendocrine marker in carcinoid tumors of lung and gastrointestinal tract, it is of paramount importance to understand the features of this protein in different environment for assigning its crucial functions in different tissues and under pathophysiological conditions. To score out the limitation of protein for in vitro studies, we report a one-step, high purity and high level bacterial purification of secretagogin by refolding from the inclusion bodies yielding about 40mg protein per litre of bacterial culture. We also report previously undocumented Ca(2+)/Mg(2+) binding and hydrodynamic properties of secretagogin.
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad 500 007, India. Electronic address: anandkumar@ccmb.res.in.
authors.forename: Anand Kumar
authors.initials: AK
authors.lastname: Sharma
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad 500 007, India.
authors.forename: Radhika
authors.initials: R
authors.lastname: Khandelwal
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad 500 007, India.
authors.forename: Yogendra
authors.initials: Y
authors.lastname: Sharma
authors.affiliation: CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad 500 007, India.
authors.forename: Vangipurapu
authors.initials: V
authors.lastname: Rajanikanth
mesh_terms: D000818:Animals; D001671:Biochemistry / Q000379:methods*; D002118:Calcium / Q000494:pharmacology; D002151:Calorimetry; D002942:Circular Dichroism; D020832:EF Hand Motifs; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism*; D005453:Fluorescence; D057446:Hydrodynamics; D008274:Magnesium / Q000378:metabolism; D051379:Mice; D055503:Protein Multimerization / Q000187:drug effects; D058849:Protein Refolding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D064046:Secretagogins / Q000737:chemistry / Q000302:isolation & purification*; D013816:Thermodynamics; D014364:Tryptophan / Q000378:metabolism
chemical_list: D064046:Secretagogins; D014364:Tryptophan; D008274:Magnesium; D002118:Calcium
keywords: CaBPs; His-tag; Oligomerization; Protein expression; Secretagogin