H-NS Oligomerization Domain Structure Reveals the Mechanism for High Order Self-association of the Intact Protein
Esposito, D., Petrovic, A., Harris, R., Ono, S., Eccleston, J., Mbabaali, A., Haq, I., Higgins, C.F., Hinton, J.C., Driscoll, P.C., Ladbury, J.E.(2002) J Mol Biol 324: 841-850
- PubMed: 12460581
- DOI: https://doi.org/10.1016/s0022-2836(02)01141-5
- Primary Citation of Related Structures:
1LR1 - PubMed Abstract:
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.
Organizational Affiliation:
Department of Biochemistry and Molecular Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK.