|
|
|
|
|
|
Functional Interaction of Region 4 of the Extracytoplasmic Function Sigma Factor FecI with the Cytoplasmic Portion of the FecR Transmembrane Protein of the Escherichia coli Ferric Citrate Transport System. Susanne Mahren, 2002.Transcriptional regulation of the ferric citrate transport genes of Escherichia coli is initiated by the binding of ferric citrate to the outer membrane protein FecA . This binding elicits a signal that is transmitted by FecR across the cytoplasmic membrane into the cytoplasm, where the sigma factor FecI directs the RNA polymerase to the promoter upstream of the fecABCDE genes . An in vivo deletion analysis using a bacterial two-hybrid system assigned the interaction of the FecR and FecI proteins to the cytoplasmic portion of the FecR transmembrane protein and region 4 of FecI . Missense mutations randomly generated by PCR were localized to region 4 of FecI, and the mutants were impaired with regard to the interaction of FecR with FecI and fecB-lacZ transcription . The cloned region 4 of FecI interfered with fecB-lacZ transcription . Interaction of N-proximal regions of predicted FecR homologs with region 4 of predicted FecI homologs of Pseudomonas aeruginosa was demonstrated . The interaction was specific in that only cognate protein pairs interacted with each other; no interactions occurred between heterologous combinations of the P . aeruginosa proteins and between a P . aeruginosa FecI homolog and E . coli FecR . The results demonstrate that region 4 of FecI specifically binds FecR and that this binding is necessary for FecI to function as a sigma factor . Genome Analysis of a Novel Shiga Toxin 1 (Stx1)-Converting Phage Which Is Closely Related to Stx2-Converting Phages but Not to Other Stx1-Converting Phages. Toshio Sato, 2003.Two Stx-converting phages, designated Stx1  and Stx2-II, were isolated from an Escherichia coli O157:H7 strain, Morioka V526, and their entire nucleotide sequences were determined . The genomes of both phages were similar except for the stx gene-flanking regions . Comparing these phages to other known Stx-converting phages, we concluded that Stx1 is a novel Stx1-converting phage closely related to Stx2-converting phages so far reported .
|
© 2005
Transgalactic Ltd (manufacturer of Bioscreen C software) |
Privacy Statement | P.O. Box
1393, 00101 Helsinki, Finland,
Last modified: May 25, 2005
| ||||||
