H-NS oligomerization domain structure reveals the mechanism for high order self-association of the intact protein.
H-NS plays a role in condensing DNA in the bacterial nucleoid. This 136 amino acid protein comprises two functional domains separated by a flexible linker. High order structures formed by the N-terminal oligomerization domain (residues 1-89) constitute the basis of a protein scaffold that binds DNA via the C-terminal domain. Deletion of residues 57-89 or 64-89 of the oligomerization domain precludes high order structure formation, yielding a discrete dimer. This dimerization event represents the initial event in the formation of high order structure. The dimers thus constitute the basic building block of the protein scaffold. The three-dimensional solution structure of one of these units (residues 1-57) has been determined. Activity of these structural units is demonstrated by a dominant negative effect on high order structure formation on addition to the full length protein. Truncated and site-directed mutant forms of the N-terminal domain of H-NS reveal how the dimeric unit self-associates in a head-to-tail manner and demonstrate the importance of secondary structure in this interaction to form high order structures. A model is presented for the structural basis for DNA packaging in bacterial cells.
Esposito
Diego
D
Department of Biochemistry and Molecular Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK.
Petrovic
Arsen
A
Harris
Richard
R
Ono
Shusuke
S
Eccleston
John F
JF
Mbabaali
Amina
A
Haq
Ihtshamul
I
Higgins
Christopher F
CF
Hinton
Jay C D
JC
Driscoll
Paul C
PC
Ladbury
John E
JE
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002247:Carbon Isotopes; D004269:DNA, Bacterial / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D005947:Glucose / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular; D009842:Oligopeptides / Q000737:chemistry; D011392:Proline / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012486:Salmonella typhimurium / Q000737:chemistry; D017384:Sequence Deletion; D012996:Solutions; D013329:Structure-Activity Relationship; D014867:Water / Q000737:chemistry
D001426:Bacterial Proteins; D002247:Carbon Isotopes; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C031908:H-NS protein, bacteria; D009587:Nitrogen Isotopes; D009842:Oligopeptides; D012996:Solutions; D014867:Water; D011392:Proline; D005947:Glucose