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Spiral structure of Escherichia coli HUalphabeta provides foundation for DNA supercoiling.

ABSTRACT: We determined the crystal structure of the Escherichia coli nucleoid-associated HUalphabeta protein by x-ray diffraction and observed that the heterodimers form multimers with octameric units in three potential arrangements, which may serve specialized roles in different DNA transaction reactions. It is of special importance that one of the structures forms spiral filaments with left-handed rotations. A negatively superhelical DNA can be modeled to wrap around this left-handed HUalphabeta multimer. Whereas the wild-type HU generated negative DNA supercoiling in vitro, an engineered heterodimer with an altered amino acid residue critical for the formation of the left-handed spiral protein in the crystal was defective in the process, thus providing the structural explanation for the classical property of HU to restrain negative supercoils in DNA.

SUBMITTER: Guo F

PROVIDER: S-EPMC1838598 | biostudies-literature | 2007 Mar

REPOSITORIES: biostudies-literature

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Spiral structure of Escherichia coli HUalphabeta provides foundation for DNA supercoiling.

Guo Fusheng F Adhya Sankar S

Proceedings of the National Academy of Sciences of the United States of America 20070305 11

We determined the crystal structure of the Escherichia coli nucleoid-associated HUalphabeta protein by x-ray diffraction and observed that the heterodimers form multimers with octameric units in three potential arrangements, which may serve specialized roles in different DNA transaction reactions. It is of special importance that one of the structures forms spiral filaments with left-handed rotations. A negatively superhelical DNA can be modeled to wrap around this left-handed HUalphabeta multim ...[more]

PMID: 17360520

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