DNA primase activity

Definition

Target type: molecularfunction

Catalysis of the synthesis of a short RNA primer on a DNA template, providing a free 3'-OH that can be extended by DNA-directed DNA polymerases. In certain conditions, for example in response to DNA damage, some primases synthesize a DNA primer. [GOC:mah, GOC:mcc, PMID:11395402, PMID:26184436, PMID:38203225, PMID:38492718]

DNA primase activity is a crucial enzymatic function that plays a vital role in DNA replication. This activity is catalyzed by DNA primases, which are enzymes that synthesize short RNA primers, typically 10-15 nucleotides long. These RNA primers are essential because DNA polymerases, the enzymes responsible for DNA replication, can only extend existing DNA strands, not initiate synthesis de novo. Here is a detailed description of the molecular function of DNA primase activity:

1. **Primer Recognition and Binding:** DNA primases bind to single-stranded DNA templates at specific sites, often at the origin of replication or at gaps in the DNA strand.

2. **RNA Primer Synthesis:** Once bound, DNA primases utilize ribonucleoside triphosphates (NTPs) as substrates to synthesize short RNA primers. The process of primer synthesis proceeds in a 5' to 3' direction, opposite to the direction of DNA replication.

3. **Primer Extension:** After primer synthesis, DNA polymerases can then bind to the primer-template complex and extend the RNA primer with DNA nucleotides, continuing the process of DNA replication.

4. **Primer Removal:** In eukaryotes, the RNA primers are subsequently removed by enzymes called RNase H and DNA polymerase I, and the gaps are filled with DNA nucleotides.

5. **Overall Role:** The activity of DNA primase is essential for initiating DNA replication and ensuring that DNA synthesis proceeds in a continuous and accurate manner. This activity is critical for cell growth, repair, and maintenance.

Overall, DNA primase activity is a critical step in DNA replication, enabling the initiation and continuation of DNA synthesis by providing the necessary RNA primers for DNA polymerase activity. This function is essential for the maintenance and propagation of genetic information in all living organisms.'
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Proteins (1)

Compounds (1)