Primase

Primase is an enzyme that synthesizes short RNA sequences known as primers. These primers serve as a starting point for DNA synthesis. Primase is a key component in the DNA replication process.

Function

Primase is essential for the replication of DNA. It synthesizes a short RNA segment, the primer, which is complementary to a DNA template. This primer provides a 3'-OH group for the attachment of DNA nucleotides. The synthesis of a primer is necessary because DNA polymerase, another enzyme involved in DNA replication, can only add nucleotides to an existing 3'-OH group.

Structure

Primase is a type of RNA polymerase, and its structure allows it to synthesize RNA primers with a DNA template. While the exact structure can vary among different organisms, the core function remains the same.

Role in DNA Replication

During DNA replication, primase is recruited to the replication fork by a complex of replication proteins. Once there, it synthesizes a short RNA primer on the lagging strand. This primer allows DNA polymerase to begin synthesizing the new DNA strand. Without the primer, DNA polymerase would not be able to begin DNA synthesis.

Clinical Significance

Mutations in the primase can lead to errors in DNA replication, which can in turn lead to genetic disorders. Additionally, some anti-cancer drugs target the function of primase, as inhibiting DNA replication can prevent the growth of cancer cells.

See Also

• DNA replication
• RNA polymerase
• DNA polymerase

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