The 3-D structure of VNG0258H/RosR – A haloarchaeal DNA-binding protein in its ionic shell

Nitzan Kutnowski, Hagay Shmuely, Idit Dahan, Fania Shmulevich, Geula Davidov, Anat Shahar, Jerry Eichler, Raz Zarivach, Boaz Shaanan

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Protein-DNA interactions are highly dependent on salt concentration. To gain insight into how such interactions are maintained in the highly saline cytoplasm of halophilic archaea, we determined the 3-D structure of VNG0258H/RosR, the first haloarchaeal DNA-binding protein from the extreme halophilic archaeon Halobactrium salinarum. It is a dimeric winged-helix-turn-helix (wHTH) protein with unique features due to adaptation to the halophilic environment. As ions are major players in DNA binding processes, particularly in halophilic environments, we investigated the solution structure of the ionic envelope and located anions in the first shell around the protein in the crystal using anomalous scattering. Anions that were found to be tightly bound to residues in the positively charged DNA-binding site would probably be released upon DNA binding and will thus make significant contribution to the driving force of the binding process. Unexpectedly, ions were also found in a buried internal cavity connected to the external medium by a tunnel. Our structure lays a solid groundwork for future structural, computational and biochemical studies on complexes of the protein with cognate DNA sequences, with implications to protein-DNA interactions in hyper-saline environments.

Original languageEnglish
Pages (from-to)191-198
Number of pages8
JournalJournal of Structural Biology
Issue number2
StatePublished - 1 Nov 2018


  • Anomalous scattering
  • Hyper-saline environment
  • Ions in crystals
  • Protein-DNA interactions
  • Salt effects

ASJC Scopus subject areas

  • Structural Biology


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