Characterization of a methyl-specific restriction system in Clostridium acetobutylicum strain N1-4081

A type II restriction endonuclease, named CacI, was detected in Clostridium acetobutylicum strain N1-4081. CacI cleaved the tetranucleotide sequence [5′↓-GATC-3′]. The modification system consisted of the methylation of the adenine present in this sequence. CacI, an isoschizomer of MboI, is inactive on dam methylated substrates.