Mammalian DNA Polymerase α Holoenzyme

Abstract

DNA replication as a macromolecular process requires the concerted action of many enzymes and proteins either alone or in a complex (1). These include e.g. DNA polymerases, DNA polymerase accessory proteins, primase, topoisomerases, helicases, DNA-binding proteins, ribonuclease H, DNA ligase and others (1). Using the DNA of small bacteriophages of Escherichia coli and of plasmids containing the oriC as model replicons to understand the host DNA replication events, it was discovered that multienzyme systems are involved (1). The DNA elongation step alone needs DNA polymerase III, the major replicase in bacteria. DNA polymerase III functions in the form of a multipolypeptide complex called DNA polymerase III holoenzyme (2). The term holoenzyme has been introduced in Escherichia coli for a complex of proteins including a core DNA polymerase III and several auxiliary proteins, which are essential for replication of primed natural single stranded genoms (2). Many details of the structure and functions of this multipolypeptide complex have emerged during the last few years (3, 4).