The Catalytic Subunit B-family of Replicative DNA...

The catalytic subunit-PolÃŽ ± Polymerase ÃŽ ± is the first mammalian polymerase detected. It is a member of the B-family of replicative DNA polymerases. Its primary role is to further extend the RNA primer by addition of deoxy-nucleotides (dNTPs) into a total of 20-25 nucleotides of RNA-DNA primer. Generally, replicative DNA polymerases, polymerize dNTPs by catalyzing nucleophilic attack of the 3’-hydroxyl group of the primer onto the ÃŽ ±-phosphate of an incoming dNTP aligned to the template strand. The accuracy of the polymerases is achieved by a confirmation of the correct base pairing of the incoming dNTP and the template strand according to Watson-Crick base-pairing. The accuracy of the primases is further enhanced (100 fold) by their exonuclease activity where in the event of a mismatch the growing strand is pushed back to the exonuclease active and the mismatched nucleotide is excised. Most of our structural knowledge of the B-family of DNA polymerases came from the structure of the prototypical family member, bacteriophage RB69 Pol (Wang et al., 1997 in elife). Followed that the structure of the bacterial DNA Pol II (Wang and Yang, 2009 in elife) and then yeast Pol ÃŽ ´ (Swan et al., 2009). Only recently, the crystal structure of the catalytic domain of the yeast Pol ÃŽ ± subunit, Pol ÃŽ ± 349–1258, has been solved (elife). The structure confirmed that Pol ÃŽ ± shares a polymerase and an exonuclease domains similar to RB69 Pol, bacterial DNA Pol II and yeast Pol ÃŽ ´. Unlike the otherShow MoreRelatedDna Analysis : Dna And Dna2142 Words   |  9 Pages DNA polymerases are vital in how an organism can sustain life. DNA polymerases are enzymes that synthesize DNA molecules from deoxyribonucleotides and are accountable for DNA replication. They are absolutely critical for DNA replication and will typically work in sets so that they can create two identical sets of DNA strands from one single strand of DNA. DNA polymerase will catalyze the reaction: deoxynucleoside triphosphate + DNAn diphosphate + DNAn+1. DNA polymerases are extremely important