You are carrying out PCRs in lab Why do you not need helicas

You are carrying out PCRs in lab. Why do you not need helicase, SSB, primase, ligase, sliding clamp?

Solution

1. Helicase: Helicase is an eznyme that plays a crucial role in seperating  the DNA double helix by unwinding it.

2. SSB: It stands for Single-Stranded DNA Binding Protein (SSB). It binds with high affinity to single-stranded DNA and destabilizes helical duplexes. This helps DNA polymerases to bind to substrates easily. SSB do not bind to double stranded DNAs.

3. Primase: Primase is an enzyme that synthesize primers (short stretches of DNA for the DNA synthesis to proceed) in vivo. In  In a PCR experiment, two specific primers are designed and added in the reaction for amplifying specific sequences.

4. Ligase: This enzyme catalyze the DNA repair process by joining of ends of DNA molecules. In these reactions, this enzyme links the phosphate to a neighboring sugar molecule, thus forming the backbone of DNA.

5. Sliding clamp: This clamp protein binds to DNA polymerase (enyme synthesizing the DNA chain), and prevents it from dissociation from the template. Thus it acts as a promoting factor in DNA replication process. The clamp-polymerase interactions are stronger and more specific. It increases the rate of reaction progression.