2an7
From Proteopedia
Solution structure of the bacterial antidote ParD
Overview
NMR and CD spectroscopy have been used to characterize, both structurally and dynamically, the 82-amino-acid ParD protein of the post-segregational killing module of the broad-host-range plasmid RP4/RK2. ParD occurs as a dimer in solution and exercises two different control functions; an autoregulatory function by binding to its own promoter P(parDE) and a plasmid-stabilizing function by inhibiting ParE toxicity in cells that express ParD and ParE. Analysis of the secondary structure based on the chemical-shift indices, sequential nuclear Overhauser enhancements (NOEs) and (3)J(Halpha-NH) scalar coupling constants showed that the N-terminal domain of ParD consists of a short beta-ribbon followed by three alpha-helices, demonstrating that ParD contains a ribbon-helix-helix fold, a DNA-binding motif found in a family of small prokaryotic repressors. (15)N longitudinal (T(1)) and transverse (T(2)) relaxation measurements and hetero nuclear NOEs showed that ParD is divided into two separate domains, a well-ordered N-terminal domain and a very flexible C-terminal domain. An increase in secondary structure was observed upon addition of trifluoroethanol, suggested to result from the formation of structured stretches in the C-terminal part of the protein. This is the first experimental evidence that the DNA-binding domain of ParD belongs to the ribbon-helix-helix fold family, and this structural motif is proposed to be present in functionally similar antidote proteins.
About this Structure
2AN7 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
The anti-toxin ParD of plasmid RK2 consists of two structurally distinct moieties and belongs to the ribbon-helix-helix family of DNA-binding proteins., Oberer M, Zangger K, Prytulla S, Keller W, Biochem J. 2002 Jan 1;361(Pt 1):41-7. PMID:11743881 Page seeded by OCA on Sat May 3 19:14:49 2008
