DNA-binding by Haemophilus influenzae and Escherichia coli YbaB, members of a widely-distributed bacterial protein family

Anne E. Cooley, Sean P. Riley, Keith Kral, M. Clarke Miller, Edward Demoll, Michael G. Fried, Brian Stevenson

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Background. Genes orthologous to the ybaB loci of Escherichia coli and Haemophilus influenzae are widely distributed among eubacteria. Several years ago, the three-dimensional structures of the YbaB orthologs of both E. coli and H. influenzae were determined, revealing a novel "tweezer"-like structure. However, a function for YbaB had remained elusive, with an early study of the H. influenzae ortholog failing to detect DNA-binding activity. Our group recently determined that the Borrelia burgdorferi YbaB ortholog, EbfC, is a DNA-binding protein. To reconcile those results, we assessed the abilities of both the H. influenzae and E. coli YbaB proteins to bind DNA to which B. burgdorferi EbfC can bind. Results. Both the H. influenzae and the E. coli YbaB proteins bound to tested DNAs. DNA-binding was not well competed with poly-dI-dC, indicating some sequence preferences for those two proteins. Analyses of binding characteristics determined that both YbaB orthologs bind as homodimers. Different DNA sequence preferences were observed between H. influenzae YbaB, E. coli YbaB and B. burgdorferi EbfC, consistent with amino acid differences in the putative DNA-binding domains of these proteins. Conclusion. Three distinct members of the YbaB/EbfC bacterial protein family have now been demonstrated to bind DNA. Members of this protein family are encoded by a broad range of bacteria, including many pathogenic species, and results of our studies suggest that all such proteins have DNA-binding activities. The functions of YbaB/EbfC family members in each bacterial species are as-yet unknown, but given the ubiquity of these DNA-binding proteins among Eubacteria, further investigations are warranted.

Original languageEnglish
Article number137
JournalBMC Microbiology
StatePublished - 2009

Bibliographical note

Funding Information:
The work was funded by NIH grant R01-AI044254 to Brian Stevenson and R01-GM070662 to Michael Fried. Sean Riley was supported in part by NIH Training Grant in Microbial Pathogenesis T32-AI49795 and a University of Kentucky Graduate School Dissertation Year Fellowship. We thank Osnat Herzberg for the generous gift of the YbaB-producing plasmid, and Amy Bowman, Catherine Brissette, Logan Burns, Tomasz Bykowski, Ashutosh Verma, Erin Welsh, and Michael Woodman for assistance during these studies and comments on the manuscript.

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)


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