5UBD

Crystal structure of the N-terminal domain (domain 1) of RctB, RctB-1-124-L48M

Summary for 5UBD

• Entry DOI: 10.2210/pdb5ubd/pdb
• Related: 5UBE 5UBF
• Descriptor: RctB replication initiator protein (2 entities in total)
• Functional Keywords: dna replication initiation, dna binding, secondary chromosome, vibrio cholerae, dna binding protein
• Biological source: Vibrio cholerae
• Total number of polymer chains: 2
• Total formula weight: 29997.67

Authors

Orlova, N.,Ivashkiv, O.,Waldor, M.K.,Jeruzalmi, D. (deposition date: 2016-12-20, release date: 2017-01-11, Last modification date: 2024-11-06)

Primary citation

Orlova, N.,Gerding, M.,Ivashkiv, O.,Olinares, P.D.B.,Chait, B.T.,Waldor, M.K.,Jeruzalmi, D.
The replication initiator of the cholera pathogen's second chromosome shows structural similarity to plasmid initiators.
Nucleic Acids Res., 45:3724-3737, 2017

PubMed Abstract: The conserved DnaA-oriC system is used to initiate replication of primary chromosomes throughout the bacterial kingdom; however, bacteria with multipartite genomes evolved distinct systems to initiate replication of secondary chromosomes. In the cholera pathogen, Vibrio cholerae, and in related species, secondary chromosome replication requires the RctB initiator protein. Here, we show that RctB consists of four domains. The structure of its central two domains resembles that of several plasmid replication initiators. RctB contains at least three DNA binding winged-helix-turn-helix motifs, and mutations within any of these severely compromise biological activity. In the structure, RctB adopts a head-to-head dimeric configuration that likely reflects the arrangement in solution. Therefore, major structural reorganization likely accompanies complex formation on the head-to-tail array of binding sites in oriCII. Our findings support the hypothesis that the second Vibrionaceae chromosome arose from an ancestral plasmid, and that RctB may have evolved additional regulatory features.

PubMed: 28031373
DOI: 10.1093/nar/gkw1288

Experimental method

X-RAY DIFFRACTION (2.002 Å)