Asymmetric allosteric activation of the symmetric ArgR hexamer

Lihua Jin, Wei Feng Xue, June Wong Fukayama, Jaclyn Yetter, Michael Pickering, Jannette Carey

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Hexameric arginine repressor, ArgR, bound to l-arginine serves both as the master transcriptional repressor/activator at diverse regulons in a wide range of bacteria and as a required cofactor for resolution of ColE1 plasmid multimers. Multifunctional ArgR is thus unusual in possessing features of specific gene regulators, global regulators, and non-specific gene organizers; its closest functional analog is probably CAP, the cyclic AMP receptor/activator protein. Isothermal titration calorimetry, surface plasmon resonance, and proteolysis indicate that binding of a single l-arginine residue per ArgR hexamer triggers a global conformational change and resets the affinities of the remaining five sites, making them 100-fold weaker. The analysis suggests a novel thermodynamic signature for this mechanism of activation.

Original languageEnglish (US)
Pages (from-to)43-56
Number of pages14
JournalJournal of Molecular Biology
Issue number1
StatePublished - Feb 11 2005

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Structural Biology


  • c value
  • cooperativity
  • global analysis
  • ligand occupancy


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