Enzymatic mechanisms of DNA replication.
DNA polymerases purified from several sources are characterized by replication of the 3'-hydroxy-terminated strand of a helical template. Failure to achieve simultaneous replication of the 5'-strand leads to aberrations in the synthesized DNA, described as nondenaturability and branching. Aberrations in synthesized DNA were not observed when (a) the 5'-strand was destroyed by a specific nuclease during the course of replication or (b) a single-stranded (circular) phage (M13) DNA served as template. Replication of a single-stranded, circular DNA produced a helical product, but the nature of initiation of a new strand by the circular template remains to be explained. Hypothetical mechanisms for simultaneous replication of the 5'-strand are presented as is the possibility that the tertiary structure of the DNA, as for example, a circular form of the helix, is of prime importance in in vivo replication.
D001435:Bacteriophages; D004247:DNA / Q000096:biosynthesis*; D003851:Deoxyribonucleases; D004926:Escherichia coli / Q000201:enzymology; D009713:Nucleotidyltransferases; D012333:RNA, Messenger / Q000096:biosynthesis
D012333:RNA, Messenger; D004247:DNA; D009713:Nucleotidyltransferases; D003851:Deoxyribonucleases