The holoenzyme assembles on replication fork DNA in three stages:

1. First the clamp loader uses hydrolysis of ATP to bind b subunits to a template primer complex.

2. Binding to DNA changes the conformation of the site on b that binds to the clamp loader, and as a result it now has a high affinity for the core polymerase

3. A t dimer binds to the core polymerase, and provides a dimerization function that binds a second core polymerase

TLS Online TPP Program

#Id: 3033

#Unit 3. Fundamental Processes

The two cores have different abilities to dissociate from DNA. This corresponds to the need to synthesize 

a continuous leading strand (where polymerase remains associated  with the template) and 

a discontinuous lagging strand (where polymerase repetitively dissociates and reassociates)

TLS Online TPP Program

#Id: 3034

#Unit 3. Fundamental Processes

The core on the leading strand is processive because its clamp keeps it on the DNA.

TLS Online TPP Program

#Id: 3035

#Unit 3. Fundamental Processes

The clamp associated with the core on the lagging strand dissociates at the end of each Okazaki fragment and reassembles for the next fragment.

TLS Online TPP Program

#Id: 3036

#Unit 3. Fundamental Processes

The helicase DnaB is responsible for interacting with the primase DnaG to initiate each Okazaki fragment.

TLS Online TPP Program

#Id: 3037

#Unit 3. Fundamental Processes

DnaB is responsible for forward movement at the replication fork.

TLS Online TPP Program

#Id: 3038

#Unit 3. Fundamental Processes

Core polymerase and the clamp dissociate at completion of Okazaki fragment synthesis and reassociate at the beginning.