Naslov
A division of labor between two paralogous SSB proteins in Streptomyces coelicolor

Autori
Paradžik, Tina ; Filić, Želimira ; Paradzik, Mladen ; Gazze, Andrea ; Bielen, Ana ; Francis, Lewis ; Dyson, Paul ; Jakimowicz, Dagmara ; Vujaklija, Dušica

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

Izvornik
Power of micorbes in industry and environment : Book of Abstract / - Zagreb : Hrvatsko mikrobiološko društvo, 2016, 30-30

ISBN
978-953-7778-14-9

Skup
Power of micorbes in industry and environment

Mjesto i datum
Krk, Hrvatska, 28.09.2016. - 01.10.2016

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
SSB proteins ; SsbA and SsbB ; S. coelicolor

Sažetak
SSB proteins are essential for cell survival. They bind ssDNA generated in the cell during DNA metabolism. However, the cellular role of SSBs is not only passive protection. SSBs interact and modulate the activities of various proteins involved in DNA replication, recombination and repair. We found that many bacterial genomes possess multiple copies of ssb genes. Moreover, the number of ssb genes can vary even among closely related species thus indicating that their evolution in Eubacteria is highly dynamic. However, the role of duplicated SSB proteins is poorly studied. We selected a multicellular prokaryote Streptomyces coelicolor, which contain two ssb genes to study the role of SSB paralogs. Gene expression suggested that SsbA and SsbB may be involved in different cellular processes. EMSA assays and fluorescent titrations showed that SsbA and SsbB bind to ssDNA with different affinity. AFM showed that high salt modulates SsbB binding affinity. The structural variations of SsbA and SsbB led us to hypothesize that SsbB binding activity might be regulated during oxidative stress in S. coelicolor. In concert, gene disruptions of ssbB showed that SsbB is important during the sporulation process. We examined the impact of removal of disulfide bridges on SsbB activity. The gene ssbB carrying cys7 mutation was not able to complement an S. coelicolor strain lacking ssbB. To shed the light on the complex mechanism of cell division in Streptomyces, we have constructed double (ssbB parB ; ssbB smc) and triple (ssbB parB smc) mutant strains carrying mutations in the ssbB gene and in the genes previously reported to be important for the chromosome segregation. The results showed more severe defects in nucleoid segregation during sporulation than previously reported for parental strains. Finally, by fluorescence microscopy we examined the localization of SsbA and SsbB proteins in streptomycete hyphae and observed occasional co-localization for these two paralogous proteins.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

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