Topological characterization of the essential Escherichia coli cell division protein FtsW

Authors

  • Beatriz Lara,

    1. Centro de Biología Molecular ‘Severo Ochoa’, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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  • Juan A Ayala

    Corresponding author
    1. Centro de Biología Molecular ‘Severo Ochoa’, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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*Corresponding author. Tel.: +34 (91) 3978083; Fax: +34 (91) 3978087, E-mail address: jayala@cbm.uam.es

Abstract

The membrane topology of Escherichia coli FtsW, a 46-kDa essential protein, was analyzed using a set of 28 ftsW–alkaline phosphatase (ftsW–phoA) and nine ftsW–β-lactamase (ftsW–bla) gene fusions obtained by in vivo and in vitro methods. The alkaline phosphatase activities or resistance pattern of cells expressing the FtsW–PhoA or FtsW–Bla fusions confirmed only eight out of 10 transmembrane segments predicted by computational methods. After comparison with the recent topology of Streptococcus pneumoniae FtsW, we could identify all the fusions in absolute agreement with the predicted model: N-terminal and C-terminal ends in the cytoplasm, 10 transmembrane segments and one large loop of 67 amino acids (E240–E306) located in the periplasm.

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