RNA Polymerase SDS page shows two very large subunits: beta (b) and beta-prime (b’), with molecular masses of 150 and 160 kD, respectively.

TLS Online TPP Program

#Id: 3161

#Unit 3. Fundamental Processes

The conserved function of the replication components extends to the clamp loader and processivity clamp as well other functions of the replisome.

The roles of RFC and PCNA are analogous to the E. coli γ clamp loader and β2 processivity unit

TLS Online TPP Program

#Id: 3168

#Unit 3. Fundamental Processes

Three different DNA polymerases make up the eukaryotic replication fork

Pol α/rimase is responsible for primer synthesis on the lagging strand.

The MCM helicase (the eukaryotic homolog of Dna B ) unwinds the dsDNA, while 

PCNA (homolog of ex) endows the complex with processivity.

TLS Online TPP Program

#Id: 3169

#Unit 3. Fundamental Processes

Sequences that are involved with termination are called ter sites. A ter site contains a short, -23-bp sequence.

TLS Online TPP Program

#Id: 3170

#Unit 3. Fundamental Processes

The ter site is recognized by a unidirectional contrahelicase (called Tus in E. coli and RTP in B. subtilis) that recognizes the consensus sequence and prevents the replication fork from proceeding.

TLS Online TPP Program

#Id: 3171

#Unit 3. Fundamental Processes

The E. coli enzyme acts by antagonizing the replication helicase in a direction a) manner by direct contact between the DnaB helicase and Tus.

TLS Online TPP Program

#Id: 3172

#Unit 3. Fundamental Processes

Deletion of the ter sites does not, however, prevent normal replication cycles from occurring, although it does affect segregation of the daughter chromosomes.