The amino acid sequence of a small DNA binding protein from the archaebacterium Sulfolobus solfataricus

The thermoacidophilic archaebacterium Sulfolobus solfataricus possesses several DNA binding proteins which may have a histone-like function. Two particularly dominant species have molecular masses of 7 and 10 kDa, respectively. We have purified one of the small proteins which occurs in relatively large amount and have determined its amino acid sequence. The protein is characterized by a high lysine content; in the N-terminal region the lysine residues occur in an alternating order: X-K-X-K-X-K-X-K. The amino acid sequence does not indicate any obvious homology to those DNA binding proteins whose sequences have been determined.