Structural analysis of a new GC-specific insertion element IS186.

A new insertion sequence, IS186, has been identified from Escherichia coli and sequenced. It contains 1336 base pairs with a terminal inverted repeat of 22 nucleotides. A long open reading frame, from an ATG codon at position 55 to a TAG termination codon at 1327, could code for a polypeptide of 424 amino acids. This element recognizes GC-rich regions as target sites for insertion.