00:01
Hello everyone, in this question we need to answer the questions about certain mechanistic aspects of the dna polymerase.
00:07
So, the ribonucleotide triphosphate containing the sugar ribose are at much higher concentration in a cell than the deoxyribonucleotide triphosphate.
00:20
So, why doesn't the dna polymerase mistakenly add the ribonucleotide to the growing dna strand during the dna replication? so, basically dna does not add the ribonucleotides on the growing dna strand because of its specificity and the tight fit of the binding pocket.
00:47
The nucleoside triphosphate must be properly situated in the catalytic site and this occurs if the bases are close enough due to proper hydrogen bond with the template strand.
01:02
If these does not fit well together, the nucleophilic sn2 attack is prevented because the 2 ' -oh is large and blocks the catalytic site.
01:15
So, due to which the ribonucleotides are not added.
01:19
Then in the next question it says that the role of the divalent metal ion in the dna polymerase active site is to change the chemical environment.
01:29
The list two ways the environmental changes and how do the divalent metals in rna polymerase differ.
01:36
So, in dna polymerase two magnesium ions are present to promote the polymerization.
01:44
One magnesium ion is juxtaposition to the oh of the last added nucleotide i .e.
01:52
At the 3 ' -oh end to the primer...