DNA polymerase alpha:primase binds at the origin

DNA polymerase alpha:primase is comprised of four subunits, p180, p70, p58, and p49. The two primase subunits, p58 and p49, form a tight complex. The p49 subunit contains the DNA primase activity and one role of p58 appears to be tethering p49 to p180, the DNA polymerase catalytic subunit. The fourth subunit, p70, binds p180 and may tether the DNA polymerase alpha:primase complex to Cdc45.

DNA多聚酶α：引物酶由四个亚基组成，分别为p180、p70、p58和p49。其中两个引物酶亚基p58和p49形成一个紧密的复合体。p49亚基包含DNA引物酶活性，而p58的一个作用似乎是将p49锚定于DNA多聚酶催化亚基p180。第四个亚基p70与p180结合，并可能将DNA多聚酶α：引物酶复合体锚定于Cdc45。