<P> As helicase unwinds DNA at the replication fork, the DNA ahead is forced to rotate . This process results in a build - up of twists in the DNA ahead . This build - up forms a torsional resistance that would eventually halt the progress of the replication fork . Topoisomerases are enzymes that temporarily break the strands of DNA, relieving the tension caused by unwinding the two strands of the DNA helix; topoisomerases (including DNA gyrase) achieve this by adding negative supercoils to the DNA helix . </P> <P> Bare single - stranded DNA tends to fold back on itself forming secondary structures; these structures can interfere with the movement of DNA polymerase . To prevent this, single - strand binding proteins bind to the DNA until a second strand is synthesized, preventing secondary structure formation . </P> <P> Clamp proteins form a sliding clamp around DNA, helping the DNA polymerase maintain contact with its template, thereby assisting with processivity . The inner face of the clamp enables DNA to be threaded through it . Once the polymerase reaches the end of the template or detects double - stranded DNA, the sliding clamp undergoes a conformational change that releases the DNA polymerase . Clamp - loading proteins are used to initially load the clamp, recognizing the junction between template and RNA primers . </P> <P> At the replication fork, many replication enzymes assemble on the DNA into a complex molecular machine called the replisome . The following is a list of major DNA replication enzymes that participate in the replisome: </P>

Describe the steps that occur in dna replication