A fission yeast gene encoding a protein that preferentially associates with curved DNA

We searched for fission yeast (Schizosaccharomyces pombe) proteins that preferentially bind to a synthetic curved DNA sequence, by means of a DNA-binding gel shift assay in the presence of an excess amount of a non-curved DNA sequence as a competitor. We identified such a protein in S. pombe. The protein, thus purified, has an apparent molecular weight of 42,000, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was suggested that this protein (42 K-protein) recognizes and binds to a curved DNA structure in a given nucleotide sequence, although it also binds to a non-curved DNA sequence with lower affinity. As its putative coding sequence, a 1.9-kilobase genomic DNA from S. pombe was cloned and sequenced. Sequencing of a cDNA clone also revealed the existence of an open reading frame, with no intron, encoding a 381-amino-acid protein with a calculated molecular mass, 41,597. This protein appears to be located in the nucleus. The predicted protein sequence revealed that the 42 K-protein exhibits no significant similarity to any other known proteins, except to a hypothetical protein of Caenorhabditis elegans.