Expression of cDNA Fragment Encoding Ligand-Binding Domain of Human Low Density Lipoprotein Receptor in Escherichia coli Cells

O. L. Runova,¹ M. Yu. Mandelshtam,¹ V. I. Golubkov,¹ V. E. Sukonina,¹ A. D. Denisenko,¹ and V. S. Gaitskhoki^1,2

¹Institute for Experimental Medicine, Russian Academy of Medical Sciences, ul. Akademika Pavlova 12, St. Petersburg, 197376 Russia; fax: (812) 234-9489; E-mail: molgen@molgen.iem.ras.spb.ru

²To whom correspondence should be addressed.

Submitted March 4, 1997; revision submitted May 7, 1997.

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To study structure--function relationships in low density lipoprotein receptor (LDLR), a key protein in human cholesterol metabolism, it is reasonable to operate with separate protein domains. To obtain highly purified functionally active LDLR ligand-binding domain, we have cloned the corresponding LDLR cDNA fragment in two expression plasmid vectors of Escherichia coli. We have developed methods to purify fusion and practically individual recombinant proteins and characterized the obtained products biochemically. Antibodies raised against fused with beta-galactosidase and individual recombinant protein have been shown to be efficient in identification of LDLR protein in crude lysates of human fibroblasts (cell line HT-1080).

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KEY WORDS: low density lipoprotein receptor, ligand-binding domain, expression plasmids, DNA cloning.

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