EphB1-Transformed Competent E. coli Cells

EphB1-Transformed Chemically Competent E. coli Cells are supplied in 10 x 50 µl vials in aqueous solution containing 10 mM sodium MOPS (pH 7.0), 75 mM CaCl2, 10 mM KCl, and 15% glycerol. Strain BL21(DE3), E. coli B strain with the DE3 lysogen, contains an IPTG (Isopropyl beta-D-1-thiogalactopyranoside)-inducible EphB1 (Ephrin type-B receptor 1) expression plasmid maintained with streptomycin/spectinomycin. These cells are compatible with most cloning vectors and are suitable for the expression and in vivo tyrosine phosphorylation of recombinant proteins. Tyrosine phosphorylation is a key regulatory mechanism in signal transduction pathways and plays a critical role in controlling protein activity, signaling, and stability. EphB1, a member of the Eph receptor tyrosine kinase family, catalyzes the transfer of a phosphate group from ATP to specific tyrosine residues on substrate proteins. EphB1-transformed competent E. coli cells express the cytoplasmic kinase domain of EphB1, allowing in vivo phosphorylation of recombinant target proteins that contain appropriate tyrosine residues or recognition motifs. This system enables the production of site-specific phosphorylated proteins in a prokaryotic host, eliminating the need for more complex eukaryotic systems. The result is an efficient method for generating homogeneous phosphoproteins suitable for downstream biochemical and structural studies.