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


Journal Article

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 beta 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/B(His) is able to bind to either half-site alone with high affinity.

Full Text

Duke Authors

Cited Authors

  • Wilbur, JS; Chivers, PT; Mattison, K; Potter, L; Brennan, RG; So, M

Published Date

  • September 20, 2005

Published In

Volume / Issue

  • 44 / 37

Start / End Page

  • 12515 - 12524

PubMed ID

  • 16156663

Pubmed Central ID

  • 16156663

International Standard Serial Number (ISSN)

  • 0006-2960

Digital Object Identifier (DOI)

  • 10.1021/bi0511080


  • eng

Conference Location

  • United States