Understanding DNA Polymerases: Functions, Classifications, and Activities

in this video we'll be discussing about the dna polymerases these are the enzymes that catalyze the

addition of nucleotides to an existing nucleic acid strand the primary function of dna polymerase

is to mediate the template-dependent synthesis of dna molecule from dntps that's deoxynucleoside triphosphates

during the process of synthesis it adds prenucleotides only to three prime end of newly forming strain

so in nutshell this dna polymerase drives dna replication and rapier within the cell

now let's see the classification of dna polymerases we have prokaryotic dna polymerases

eukaryotic dna polymerases and viral dna polymerases in prokaryotic dna polymerases we have

dna polymerase 1 polymerase 2 polymerase 3 polymerase 4 polymerase 5 and polymer is d

the polymerase 1 2 3 belongs to family abc respectively and polymerase 4 and 5 belongs to family y of dna polymerases

and the last polymer is that polymerase d belongs to family d then we have eukaryotic dna polymerases

as alpha delta and epsilon from family b of dna polymerases next is beta polymerase lambda polymerase sigma

polymerase mu polymerase and tdt polymerase from family x of polymerases moving further we have gamma polymerase

theta polymerase and new polymerase from family a of dna polymerases and we also have eta iota and kappa dna

polymerases from family y then we have some organism specific dna polymerases like a real family

these proteins act as dna polymerases in some eukaryotes like we have re one that's rev1 aka the oxite ideal

transferase it adds to y family of dna polymerases and we also have root 3 rib 7 complex

referred to as polymerase zeta from b family of dna polymerases now getting to the viral dna polymerases

first we have the t4 dna polymerase and t7 dna polymerase that are found in bacteriophiles

we also have reverse transcriptase enzyme which is rna dependent dna polymerase in retroviruses

now let's explain the prokaryotic dna polymerases in detail like we are going to see its polymerase

activity and its exonuclease activity first we have the dna polymerase one it mediates gap link after rna primary mole

from lagging strand it also adds in removal of primer then this dna polymerase one can also

drive dna repair pathways now getting to its exonuclease activity we see it has both exonuclease activity pi prime to

three prime as well as three prime to five prime activity we see during the process of replication

we get the lagging strand with rna primers and it's by the exonuclease activity of dna polymerase 1 which

removes primals between okazaki fragments of lagging strand and the gap between okazaki fragments is

pillared by the same dna polymerase 1 by its primary polymerase activity furthermore when we look into the

exonuclease activity of dna polymerase one the pi prime to three prime activity is its primary activity of dna

polymerase its dna dependent dna polymerase activity it requires a three prime sight and a template strained

then there is three prime to five prime activity its exonuclease activity that mediates proof reading

then we have five prime to three prime exonuclease activity that mediates nick translation during dna arabia

now getting to the polymerase 2 it drives dna vapor mechanisms and it has only 3 prime to 5 prime exonuclease

activity and finally where the polymerase 3 is the man replication enzyme that drives

dna replication proof reading and some editing processes this enzyme also has three prime to five

prime exonuclease activity only that's shown by the epsilon subunit of dna polymerase 3

then we have the dna polymerase 4 that drives translation synthesis and this translation synthesis is due to the

replication bypass of 8 oxogonin now moving towards the dna polymerase 5 which is involved in sos

response and translation synthesis during dna arapia and finally where the polymerase d

it mediates dna replication in few arcanes this polymer hd is different from other

polymerase enzymes due to its heterodimeric structure we see one monomer of polymerase d

that's dp1 it shows 3 prime to 5 prime exonuclease activity and the other monomer is dp2 which shows polymerase

activity so this is the classification of dna polymerases and the prokaryotic dna

polymerases in detail i hope you like the video if you like it give it a thumbs down to support my work on

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