Abstract

PriB is a primosomal protein that catalyzes DNA replication in Procaryota. The replication pathway starts with PriA protein - the initiator protein that binds to a DNA replication fork, unwinds double-stranded DNA and role of PriB is to stabilize PriA on the DNA. However there are many biochemical differences in replication mechanism in bacteria and only some of them use PriB proteins. A few of PriB proteins were published and only three structures of them were resolved (Escherichia coli, Klebsiellapneumoniae and Neisseria gonorrhoeae). All up-to-date known PriB proteins have one OB domain per monomer and they are homodimers in solution. Recently, we have published the crystal structure of PriB protein from Thermoanaerobactertengcongensis that represents new class of PriB with two oligonucleotide/oligosaccharide-binding domain (OB) per monomer that means it exists as monomer in solution. The aim of this study is identification and characterization of the primosomal protein B (PriB) from bacterium Clostridium pastuerianum(CpaPriB). It is the largest known bacterial PriB protein consisting 234 amino acid residues with a calculated molecular mass of 30kDa. Surprisingly, it is functional as monomer containing two single-stranded DNA binding domain (OB-fold) and it is the completely new kind structure of SSB protein like PriB protein from thermophilic bacterium Thermoanaerobactertengcongensis.Therefore, our studies suggest that we discovered new classes of PriB from mesophilic bacteria.

Authors (3)