This entry represents the alpha-helical domain of the glycinyl, putrescine and serinyltransferases (grouped as amino acid:DNA transferases, formerly known as alpha-putrescinyl/glutamylthymidine pyrophosphorylases (aGPT-Pplases) [1]) which catalyse thymidine hypermodifications in the viral genome [1-3], transferring glycine, putrescine or serine to 5-phosphomethyl-2'-deoxyuridine (5-PmdU) to produce Nalpha-GlyT, Nalpha-PutT and O-SerT, respectively. These modifications probably prevent degradation of the viral genome by the host restriction-modification antiviral defense system [2].

1: Computational identification of novel biochemical systems involved in oxidation, glycosylation and other complex modifications of bases in DNA. Iyer LM, Zhang D, Burroughs AM, Aravind L; Nucleic Acids Res. 2013;41:7635-7655. PMID:23814188

2: Pathways of thymidine hypermodification. Lee YJ, Dai N, Muller SI, Guan C, Parker MJ, Fraser ME, Walsh SE, Sridar J, Mulholland A, Nayak K, Sun Z, Lin YC, Comb DG, Marks K, Gonzalez R, Dowling DP, Bandarian V, Saleh L, Correa IR, Weigele PR; Nucleic Acids Res. 2022;50:3001-3017. PMID:34522950

3: Identification and biosynthesis of thymidine hypermodifications in the genomic DNA of widespread bacterial viruses. Lee YJ, Dai N, Walsh SE, Muller S, Fraser ME, Kauffman KM, Guan C, Correa IR Jr, Weigele PR; Proc Natl Acad Sci U S A. 2018;115:E3116. PMID:29555775