22 Describe all the processes that contribute to the high fi

22: Describe all the processes that contribute to the high fidelity of DNA replication.

Note: please site sources

Solution

Answer= processes that contribute to high fidelity of DNA replication

If DNA polymerase did nothing special when amisspairing occure between incoming deoxyribonucleoside triphosphate & DNA template the wrong nucleotide would often be incorporated into new DNA chain produces frequent mutations

The high fidelity of DNA replication depends on complementary base pairing & several proofreading mechanisms that act sequencialy to correct any initial misspairing that might have occured

1] first proofreading step is carried out by DNA polymerase = is occure just before a new nucleotide chain is added to growing chain

correct nucleotide can base pair with template

moreover after nucleotide binding , but before nucleotide is covalently added to growing chain , an enzyme undergoes a conformational change

An incorrectly bound nucleotide dissociates during this step

2] Exonuclease proofreading = It involves scanning the termini of nascent DNA chains for errors & correcting them before continuing chain extension

this process is carried out by 3^, -5^, exonuclease activity of DNA polymerase

it clips off the unpaired base or bases

In this way DNA polymerase functions as self correcting enzyme that removes its own polymerization error