Naslov
SsbB plays an important role in chromosome segregation during reproductive growth of Streptomyces coelicolor

Autori
Paradžik, Tina ; Filić, Želimira ; Ivić, Nives ; Bielen, Ana ; Manjasetty, Babu ; Herron, Paul ; Jakimowicz, Dagmara ; Luić, Marija ; Vujaklija, Dušica

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
ISBA '17 Book of Abstact / - Izmir, 2014, 102-102

ISBN
978-606-65121-0-0

Skup
XVII International Symposium on the Biology of Actinomycetes, ISBA '17 and Satellite Meeting: Application and Biotechnology of Actinomycetes

Mjesto i datum
Aydın, Turska; Kuşadası, Turska, 08.10.2014. - 12.10.2014

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
SSB; chromosome segregation; Streptomyces coelicolor

Sažetak
Single stranded DNA binding proteins (SSB) proteins are essential for cell survival in all domains of life. The SSB proteins bind ssDNA with a high affinity and in a sequence independent manner. Thus these proteins protect transiently formed ssDNA in the cell during DNA metabolism and prevent formation of unproductive secondary structures. In addition, during DNA replication, recombination and repair SSB proteins interact and modulate the functions of various proteins involved in all aspects of DNA metabolism. Our recent bioinformatics analysis of available bacterial genomes revealed the presence of the SSB parologues in many bacteria and indicated that evolution of SSB proteins in Eubacteria is highly dynamic. However the role of duplicated SSB proteins is poorly studied. In this study we selected Streptomyces coelicolor, bacterium with complex life style that also possesses two SSBs, as a good model system to study biological role(s) of paralogous SSB proteins. Differential regulation of paralogous ssb genes in S. coelicolor suggested different roles for their products. Expression of ssbA is constant and high during life cycle, decreasing towards late stationary phase, while the expression of ssbB is at all-time low. In minimal medium the ssbB is significantly upregulated. Promoters for both genes are determined. Surprisingly, promoter of ssbB possesses unusual features and is active in taxonomically distant Escherichia coli. Results of the gene disruptions strongly indicated that SsbA is essential for survival while SsbB is important during the sporulation process. To get a better insight into the role of SsbB and the complex mechanism of cell division in Streptomyces we have constructed double and triple mutant strains carrying mutations in ssbB gene and genes reported previously to be important for the chromosomal segregation (parB and smc). By fluorescence microscopy we showed the effect of these mutations on chromosome segregation. In addition to genetic analysis we solved the 3D structure of SsbB and showed an interesting variation in comparison to quaternary structure of the previously published S. coelicolor SsbA protein. To the best of our knowledge this is the first example of solved crystal structures of two paralogous SSB proteins from the same organism.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Biologija

POVEZANOST RADA