Vibriophage phiVC8 DpoZ: Difference between revisions

[[Vibriophage phiVC8 DpoZ]] is a [[DNA polymerase]] belonging to the PolA family and the ΦVC8-like DpoZ subfamily, a group currently identified in certain species of bacteriophages<ref>PMID:34751404</ref>. DpoZ consists of two subfamilies: ΦVC8-like and Wayne-like. These polymerases confer selectivity in addition of the nucleobase 2-aminoadenine (Z) over adenine (A), with A completely ablated from their genomes. Z forms a non Watson-Crick base pair with thymine (T) consisting of three hydrogen bonds as opposed to the two present in A-T base pairing. Z is a relatively novel discovery, having only recently had its biosynthetic pathway described in detail<ref>PMID:33926954</ref>. DNA modifications in bacteriophages usually confer selective advantages by allowing phages to avoid host cell restriction enzyme digestion of their genomes<ref>Weigele, P., & Raleigh, E. A. (2016). Biosynthesis and Function of Modified Bases in Bacteria and Their Viruses. <i>Chemical Reviews</i>, <i>116</i>(20), 12655–12687. https://doi.org/10.1021/acs.chemrev.6b00114</ref>. The phage S-2L has a Z genome and encodes a [https://www.ncbi.nlm.nih.gov/gene/201973 PrimPol polymerase] as well as a nucleotide phosphohydrolase called [https://www.rcsb.org/structure/6ZPB DatZ] that removes the triphosphate tail of only dATP, excluding it from the genome<ref>PMID:33893297</ref>. Vibriophage ΦVC8 also encodes DatZ<ref>PMID:34751404</ref>, though it is unknown if it is the primary enzyme responsible for A exclusion or if its polymerase also plays a role. The specific mechanisms by which ΦVC8-like DpoZ polymerases carry out A exclusion and Z inclusion are still under investigation, though specific structural features and putative specificity mechanisms are highlighted below.