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A B Poulsen

Publications and source records attributed to A B Poulsen.

2 recordsLinked to original sources
PubMed1997

E. coli translation initiation factor IF2--an extremely conserved protein. Comparative sequence analysis of the infB gene in clinical isolates of E. coli.

The functionally uncharacterised N-terminal of translation initiation factor IF2 has been found to be extremely variable when comparing different bacterial species. In order to study the intraspecies variability of IF2 the 2670 basepairs nucleotide sequence of the infB gene (encoding IF2) was determined in 10 clinical isolates of E. coli. The N-terminal domains (I, II and III) were completely conserved indicating a specific function of this region of IF2. Only one polymorphic position was found in the deduced 890 amino acid sequence. This Gln/Gly490 is located within the central GTP/GDP-binding domain IV of IF2. The results are further evidence that IF2 from E. coli has reached a highly defined level of structural and functional development.

Conserved Sequence↗
PubMed1994

Protease activity of outer membrane protein OmpT in clinical E.coli isolates--studies using translation initiation factor IF2 as target protein.

During purification of the translation initiation factor IF2 from ompT+ strains of Escherichia coli the IF2 is partially degraded in the presence of membrane debris during the first steps of purification. This is a result of proteolytic cleavage by outer membrane protease OmpT [1]. Here we have investigated the activity of OmpT in 51 clinical E. coli isolates of human origin, by a time dependent OmpT activity assay using IF2 as target protein. The activity of OmpT in the outer cell membrane is highly variable among wild type E.coli strains, ranging from no detectable activity in 65% of the strains to a very high activity in 5 strains (10%). The OmpT activity is closely related to the assay temperature and to the growth temperature of the cells, and can be reduced or even eliminated by lowering the temperature of growth. The results open the possibility of using non-denaturing gel electrophoresis of crude cell lysates as a screening method in population genetic studies of initiation factor IF2 and other cytoplasmic proteins which are cleaved by OmpT.

Cell Division↗