Proteins play several important roles in DNA replication. One of the most important proteins involved in DNA replication is DNA polymerase, which is responsible for adding nucleotides to the growing DNA strand. Other proteins, such as helicase and topoisomerase, help to unwind and untangle the DNA double helix so that it can be replicated. Enzymes called primases help to create RNA primers, which DNA polymerase uses as a starting point for adding nucleotides to the new DNA strand. Finally, proteins such as ligase help to seal the gaps between the newly synthesized DNA fragments, creating a continuous strand of DNA.