Identification and validation of FepA 3D structure and its topology in E. Coli

To enter a Gram-negative bacterial cell, a solute must cross two membranes: it must first be transported across the outer membrane into the periplasmic space, and then has to cross the inner membrane to enter the cytoplasm. Proteins of the outer membrane are particularly amenable to structure determination by X-ray crystallography. Escherichia coli cells accumulate ferric (Fe3+) ions by transport of a siderophore a small cyclic peptide or related molecule which chelates the ferric ion and retains it in solution. The structures of two related outer membrane proteins, FhuA and FepA, which transport different siderophore–iron complexes ferrichrome–iron and enterobactin–iron, respectively have recently been solved. Indeed, three structures have appeared almost simultaneously two independent structures for FhuA and one for FepA. The import of siderophore–iron complexes into E. coli cells is an example of TonB-mediated transport. The siderophore receptor, either FhuA or FepA, spans the outer membrane and interacts with TonB, aprotein that traverses the ‘periplasmic’ space between the outer and inner membrane. The production of antibody against FepA may contribute to protection against Gram-negative bacteria with higher fepA gene homologies. On the basis of the above criteria the present work was designed focusing on the structure and topology prediction of the fepA protein.

کلیدواژه ها:

fepA ، E. coli ، enterobactin–iron ، structure and topology prediction