6fm1
From Proteopedia
Deoxyguanylosuccinate synthase (DgsS) quaternary structure with ATPanddGMP at 2.3 Angstrom resolution
Structural highlights
FunctionPURZ_BPVC8 Involved in the synthesis of the atypical nucleotide dZTP (2-amino-2'-deoxyadenosine-5'-triphosphate) (PubMed:33926954). Catalyzes the condensation of aspartate with deoxyguanylate into dSMP (N6-succino-2-amino-2'-deoxyadenylate), which undergoes defumarylation and phosphorylation respectively by host PurB and guanylate/nucleoside diphosphate kinases to give dZTP (PubMed:33926955). dZTP is integrated into the viral genome instead of adenine by the viral DNA polymerase. This Z-base probably completely replaces adenosine and forms a triple bond to the opposite T-base (PubMed:33926955). The resulting non-standard viral DNA is called Z-genome (PubMed:33926955). The chemically modified DNA is probably harder for the host bacteria to digest with nucleases or restriction enzymes (Probable).[HAMAP-Rule:MF_04166][1] [2] Publication Abstract from PubMedCells have two purine pathways that synthesize adenine and guanine ribonucleotides from phosphoribose via inosylate. A chemical hybrid between adenine and guanine, 2-aminoadenine (Z), replaces adenine in the DNA of the cyanobacterial virus S-2L. We show that S-2L and Vibrio phage PhiVC8 encode a third purine pathway catalyzed by PurZ, a distant paralog of succinoadenylate synthase (PurA), the enzyme condensing aspartate and inosylate in the adenine pathway. PurZ condenses aspartate with deoxyguanylate into dSMP (N6-succino-2-amino-2'-deoxyadenylate), which undergoes defumarylation and phosphorylation to give dZTP (2-amino-2'-deoxyadenosine-5'-triphosphate), a substrate for the phage DNA polymerase. Crystallography and phylogenetics analyses indicate a close relationship between phage PurZ and archaeal PurA enzymes. Our work elucidates the biocatalytic innovation that remodeled a DNA building block beyond canonical molecular biology. A third purine biosynthetic pathway encoded by aminoadenine-based viral DNA genomes.,Sleiman D, Garcia PS, Lagune M, Loc'h J, Haouz A, Taib N, Rothlisberger P, Gribaldo S, Marliere P, Kaminski PA Science. 2021 Apr 30;372(6541):516-520. doi: 10.1126/science.abe6494. PMID:33926955[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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