The nucleotide sequence of the HhaII restriction and modification genes from Haemophilus haemolyticus

We have determined the nucleotide sequence of a cloned 1710-bp segment of Haemophilus haemolyticus DNA which contains the HhaII restriction ( r) and modification ( m) genes. The m gene is 513 bp in length and the r gene is 681 bp in length. Both are in the same reading frame, being separated by a 21-bp region. A ribosome-binding site is identified in front of each gene, but no Haemophilus promoter is apparent on the cloned fragment. Transcription originates from a plasmid promoter and proceeds in the direction m to r.