Two types of bacterial telomeres of linear genomes are known. One type involves the covalent attachment of a terminal protein to each of the 5'-ends and the protective terminal protein is part of the priming complex in new rounds of DNA replication. The second type is a protein free DNA end in which one strand of the DNA duplex turns around and becomes its own complement. In the latter case, the telomere ends are copied into inverted repeats as replication proceeds around the hairpin ends and the resultant two halves of the inverted repeat are then resolved by a dimeric protein called protelomerase to form two new hairpin ends. Both of these telomere systems are found in bacteria and bacteriophages.