Similarities between the DNA replication initiators of Gram-negative bacteria plasmids (RepA) and eukaryotes (Orc4p)/archaea (Cdc6p).
The proteins responsible for the initiation of DNA replication are thought to be essentially unrelated in bacteria and archaea/eukaryotes. Here we show that RepA, the initiator from the Pseudomonas plasmid pPS10, and the C-terminal domain of ScOrc4p, a subunit of Saccharomyces cerevisiae (Sc) origin recognition complex (ORC), share sequence similarities. Based on biochemical and spectroscopic evidence, these similarities include common structural elements, such as a winged-helix domain and a leucine-zipper dimerization motif. We have also found that ScOrc4p, as previously described for RepA-type initiators, interacts with chaperones of the Hsp70 family both in vitro and in vivo, most probably to regulate the assembly of active ORC. In evolutionary terms, our results are compatible with the recruitment of the same protein module for initiation of DNA replication by the ancestors of present-day Gram-negative bacteria plasmids, archaea, and eukaryotes.
Giraldo
R
R
Department of Molecular Microbiology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Cientificas, c/Velázquez 144, 28006 Madrid, Spain. rgiraldo@cib.csic.es
Diaz-Orejas
R
R
D000595:Amino Acid Sequence; D001105:Archaea / Q000737:chemistry* / Q000235:genetics; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D004265:DNA Helicases; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins; D019143:Evolution, Molecular; D006090:Gram-Negative Bacteria / Q000737:chemistry* / Q000235:genetics; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D016350:Leucine Zippers; D008958:Models, Molecular; D008969:Molecular Sequence Data; D051738:Origin Recognition Complex; D010802:Phylogeny; D010957:Plasmids / Q000235:genetics; D011485:Protein Binding; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D011549:Pseudomonas / Q000737:chemistry / Q000235:genetics; D018741:Replication Origin / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D015534:Trans-Activators
C066503:CDC6 protein, S cerevisiae; D018797:Cell Cycle Proteins; D002843:Chromatin; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D051738:Origin Recognition Complex; D021122:Protein Subunits; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; C045264:replication initiator protein; C063842:dnaK protein, E coli; D004265:DNA Helicases