Cloning, purification, crystallization and X-ray crystallographic analysis of the periplasmic sensing domain of Pseudomonas fluorescens chemotactic transducer of amino acids type A (CtaA)

Abu Iftiaf Md Salah Ud-Din, Anna Roujeinikova

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Chemotaxis towards nutrients plays a crucial role in root colonization by Pseudomonas fluorescens. The P. fluorescens chemotactic transducer of amino acids type A (CtaA) mediates movement towards amino acids present in root exudates. In this study, the periplasmic sensory domain of CtaA has been crystallized by the hanging-drop vapor diffusion method using ammonium sulfate as a precipitating agent. A complete data set was collected to 1.9 Å resolution using cryocooling conditions and synchrotron radiation. The crystals belong to space group I222 or I212121, with unit-cell parameters a = 67.2, b = 76.0, c = 113.3 Å. This is an important step towards elucidation of the structural basis of how CtaA recognizes its signal molecules and transduces the signal across the membrane.
Original languageEnglish
Pages (from-to)320-324
Number of pages5
JournalBioScience Trends
Issue number4
Publication statusPublished - 2016


  • Bacterial chemotaxis
  • Chemoreceptor
  • Sensing domain
  • Symbiosis

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