Analysis of Escherichia coli TonB membrane topology by use of PhoA fusions. |
| |
| Authors: | S K Roof J D Allard K P Bertrand K Postle |
| |
| Affiliation: | Department of Microbiology, Washington State University, Pullman 99164-4233. |
| |
| Abstract: | Alkaline phosphatase (PhoA) fusions to TonB amino acids 32, 60, 125, 207, and 239 (the carboxy terminus) all showed high PhoA activity; a PhoA fusion to TonB amino acid 12 was inactive. The full-length TonB-PhoA fusion protein was associated with the cytoplasmic membrane and retained partial TonB function. These results support a model in which TonB is anchored in the cytoplasmic membrane by its hydrophobic amino terminus, with the remainder of the protein, including its hydrophobic carboxy terminus, extending into the periplasm. |
| |
| Keywords: | |
|
|
