Open AccessThe absence of inorganic salt is required for the crystallization of the complete oligomerization domain of Salmonella typhimurium histone‐like nucleoid‐structuring protein
Author(s) -
Leonard Paul G.,
Parkinson Gary N.,
Gor Jayesh,
Perkins Stephen J.,
Ladbury John E.
Publication year - 2010
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309110004574
Subject(s) - nucleoid , homotetramer , crystallization , histone , crystallography , chemistry , biophysics , homogeneous , dna , biochemistry , biology , gene , protein subunit , escherichia coli , physics , organic chemistry , thermodynamics
The histone‐like nucleoid‐structuring protein (H‐NS) plays an important role in both DNA packaging and global gene regulation in enterobacteria. Self‐association of the N‐terminal domain results in polydisperse oligomers that are critical to the function of the protein. This heterogeneity in oligomer size has so far prevented structure determination of the complete oligomerization domain by NMR or X‐ray crystallography. In the absence of inorganic salt, the H‐NS oligomerization domain is predominantly restricted to an equilibrium between a homodimer and homotetramer, allowing a protein solution to be prepared that is sufficiently homogeneous for successful crystallization. Crystallization was achieved by tailoring the conditions screened to those identified as minimizing the potential disruption of protein‐solution homogeneity. This finding provides a significant step towards resolving the structure of this important prokaryotic protein.