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Open Access Highly Accessed Research article

The cyanobacterial cell division factor Ftn6 contains an N-terminal DnaD-like domain

Martial Marbouty, Cyril Saguez* and Franck Chauvat*

Author Affiliations

CEA, iBiTec-S, SBIGeM, LBI, Bat 142 CEA-Saclay, F-91191 Gif sur Yvette CEDEX, France

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BMC Structural Biology 2009, 9:54  doi:10.1186/1472-6807-9-54

Published: 21 August 2009

Abstract

Background

DNA replication and cell cycle as well as their relationship have been extensively studied in the two model organisms E. coli and B. subtilis. By contrast, little is known about these processes in cyanobacteria, even though they are crucial to the biosphere, in utilizing solar energy to renew the oxygenic atmosphere and in producing the biomass for the food chain. Recent studies have allowed the identification of several cell division factors that are specifics to cyanobacteria. Among them, Ftn6 has been proposed to function in the recruitment of the crucial FtsZ proteins to the septum or the subsequent Z-ring assembly and possibly in chromosome segregation.

Results

In this study, we identified an as yet undescribed domain located in the conserved N-terminal region of Ftn6. This 77 amino-acids-long domain, designated here as FND (Ftn6

    N
-
    T
erminal
    D
omain), exhibits striking sequence and structural similarities with the DNA-interacting module, listed in the PFAM database as the DnaD-like domain (pfam04271). We took advantage of the sequence similarities between FND and the DnaD-like domains to construct a homology 3D-model of the Ftn6 FND domain from the model cyanobacterium Synechocystis PCC6803. Mapping of the conserved residues exposed onto the FND surface allowed us to identify a highly conserved area that could be engaged in Ftn6-specific interactions.

Conclusion

Overall, similarities between FND and DnaD-like domains as well as previously reported observations on Ftn6 suggest that FND may function as a DNA-interacting module thereby providing an as yet missing link between DNA replication and cell division in cyanobacteria. Consistently, we also showed that Ftn6 is involved in tolerance to DNA damages generated by UV rays.