Purification of E. coli invasin IbeA-binding protein in intestinal epithelial cells / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To purify IbeA-binding protein from intestinal epithelial Caco-2 cells.</p><p><b>METHODS</b>Recombinant IbeA was purified, and 1, 5, and 10 microg/ml His-IbeA and bovine serum albumin (control) were preincubated with confluent Caco-2 monolayer for 30 min at 4degrees celsius;. Gentamicin protection assay was used to test the invasion of E. coli K1 pathogenic isolate E44 in Caco-2 cells. The binding proteins were purified from Caco-2 by IbeA-Cu(2+) sepharose affinity chromatography, and validated by Far-Western blotting. The N-terminal amino acid sequence of the binding protein was determined using Edman assay.</p><p><b>RESULTS</b>E44 invasion in Caco-2 cells was blocked by the recombinant IbeA in a dose-dependent manner. Two binding bands were obtained with His pull-down, and the binding specificity was demonstrated by Far-Western blotting. The N-terminal amino acid sequence of IBP200 was MASITKLP with an isoelectric point of about 5.0.</p><p><b>CONCLUSION</b>Two novel Caco-2 proteins interacting with IbeA of E. coli have been purified and identified.</p>