A novel bend of DNA CIT: changeable bending-center sites of an intrinsic curvature under temperature conditions.

We found a novel DNA curvature, which has changeable bending-center sites of an intrinsic curvature under temperature conditions (CIT) in the cyanobacterium strain Microcystis aeruginosa K-81. Circular permutation analyses (CPA) for CIT under different temperature conditions (4-50 degrees C) revealed that the changeable bending-center sites are located in the 5'-upstream region (-141 to -184) of the psbA2 gene, encoding the D1 protein homolog for photosynthesis. The nucleotide sequence around the bending center contains several dT (deoxy thymine) tracts, which seem to be a pivotal determinant for CIT.