Neisseria gonorrhoeae FitA interacts with FitB to bind DNA through its ribbon-helix-helix motif

J. Scott Wilbur, Peter T. Chivers, Kirsten Mattison, Laura Potter, Richard G. Brennan, Magdalene So

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


The fit locus, encoding two proteins, FitA and FitB, was identified in a genetic screen for Neisseria gonorrhoeae determinants that affect trafficking across polarized epithelial cells. To better understand how the locus may control these activities, we have undertaken a biochemical analysis of FitA and FitB. FitA is a DNA-binding protein with a putative ribbon-helix-helix (RHH) motif. Purified FitA forms a homodimer that binds a 150 bp fit promoter sequence containing the translational start site. A putative β strand mutant of FitA, FitA(R7A), is unable to bind this DNA, supporting further that FitA is a RHH protein. FitB interacts with FitA to form a 98 kDa complex. FitA/B binds DNA with a 38-fold higher affinity than the FitA homodimer. In DNase I footprint assays, FitA/B protects a 62-bp region within the fit promoter containing the predicted -10 sequence and an 8-bp inverted repeat, TGCTATCA-N 12-TGATAGCA. FitA/BHiS is able to bind to either half-site alone with high affinity.

Original languageEnglish (US)
Pages (from-to)12515-12524
Number of pages10
Issue number37
StatePublished - Sep 20 2005

ASJC Scopus subject areas

  • Biochemistry


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