Giant Virus Megavirus chilensis Encodes the Biosynthetic Pathway for Uncommon Acetamido Sugars

Piacente, Francesco; Castro, Cristina De; Jeudy, Sandra; Molinaro, Antonio; Salis, Annalisa; Damonte, Gianluca; Bernardi, Cinzia; Abergel, Chantal; Tonetti, Michela

doi:10.1074/jbc.m114.588947

Cited by 24 publications

(45 citation statements)

References 41 publications

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“…However, because these putative GTs are only found in Mimiviridae members of group A, it is likely that they are involved in the transfer of the monosaccharides that are uniquely produced by these viruses, i.e. rhamnose and Vio (6,7).…”

Section: Discussionmentioning

confidence: 99%

“…The reactions were stopped by heat inactivation for 3 min at 80°C at different time points of incubation, and the solutions were clarified by microfiltration (Millipore). After clarification, the reaction mixtures were analyzed by HPLC, as previously described (7). Specific activity was determined using the reduction of UDP-D-Vio peak area and expressed as means Ϯ S.D.…”

Section: Enzymatic Assaysmentioning

confidence: 99%

“…The dry permethylated particles were hydrolyzed with TFA and further processed to obtain the alditol acetate derivatives, as previously described (7). The PMAA were extracted from the solid crust at the bottom of the vial four times with 0.5 ml of dichloromethane and collected in a new vial.…”

Section: Analysis Of Vionac Presence On Mimivirus Glycanmentioning

confidence: 99%

“…The PMAA were extracted from the solid crust at the bottom of the vial four times with 0.5 ml of dichloromethane and collected in a new vial. The samples, evaporated and suspended in a small volume of dichloromethane, were analyzed by GC-MS as previously described (7).…”

Section: Analysis Of Vionac Presence On Mimivirus Glycanmentioning

confidence: 99%

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The rare sugar N-acetylated viosamine is a major component of Mimivirus fibers

Piacente

Castro²,

Jeudy

et al. 2017

Journal of Biological Chemistry

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The giant virus Mimivirus encodes an autonomous glycosylation system that is thought to be responsible for the formation of complex and unusual glycans composing the fibers surrounding its icosahedral capsid, including the dideoxyhexose viosamine. Previous studies have identified a gene cluster in the virus genome, encoding enzymes involved in nucleotide-sugar production and glycan formation, but the functional characterization of these enzymes and the full identification of the glycans found in viral fibers remain incomplete. Because viosamine is typically found in acylated forms, we suspected that one of the genes might encode an acyltransferase, providing directions to our functional annotations. Bioinformatic analyses indicated that the L142 protein contains an N-terminal acyltransferase domain and a predicted C-terminal glycosyltransferase. Sequence analysis of the structural model of the L142 N-terminal domain indicated significant homology with some characterized sugar acetyltransferases that modify the C-4 amino group in the bacillosamine or perosamine biosynthetic pathways. Using mass spectrometry and NMR analyses, we confirmed that the L142 N-terminal domain is a sugar acetyltransferase, catalyzing the transfer of an acetyl moiety from acetyl-CoA to the C-4 amino group of UDP-d-viosamine. The presence of acetylated viosamine has also been confirmed on the glycosylated viral fibers, using GC-MS and NMR. This study represents the first report of a virally encoded sugar acetyltransferase.

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Section: Discussionmentioning

confidence: 99%

Section: Enzymatic Assaysmentioning

confidence: 99%

Section: Analysis Of Vionac Presence On Mimivirus Glycanmentioning

confidence: 99%

Section: Analysis Of Vionac Presence On Mimivirus Glycanmentioning

confidence: 99%

See 2 more Smart Citations

The rare sugar N-acetylated viosamine is a major component of Mimivirus fibers

Piacente

Castro²,

Jeudy

et al. 2017

Journal of Biological Chemistry

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“…Mimiviridae are among its largest members, with particle sizes that make them visible by light microscopy and genome complexities overlapping those of the cellular world. They encode proteins thought to be the trademarks of cells, such as elements of the translation machinery as well as original metabolic pathways (3)(4)(5)(6)(7). Megavirus chilensis was isolated from an environmental sample from the coast of central Chile by cocultivation with Acanthamoeba castellanii (8).…”

mentioning

confidence: 99%

The Megavirus Chilensis Cu,Zn-Superoxide Dismutase: the First Viral Structure of a Typical Cellular Copper Chaperone-Independent Hyperstable Dimeric Enzyme

Lartigue

Burlat

Coutard

et al. 2015

J Virol

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Giant viruses able to replicate in Acanthamoeba castellanii penetrate their host through phagocytosis. After capsid opening, a fusion between the internal membranes of the virion and the phagocytic vacuole triggers the transfer in the cytoplasm of the viral DNA together with the DNA repair enzymes and the transcription machinery present in the particles. In addition, the proteome analysis of purified mimivirus virions revealed the presence of many enzymes meant to resist oxidative stress and conserved in the Mimiviridae. Megavirus chilensis encodes a predicted copper, zinc superoxide dismutase (Cu,Zn-SOD), an enzyme known to detoxify reactive oxygen species released in the course of host defense reactions. While it was thought that the metal ions are required for the formation of the active-site lid and dimer stabilization, megavirus chilensis SOD forms a very stable metal-free dimer. We used electron paramagnetic resonance (EPR) analysis and activity measurements to show that the supplementation of the bacterial culture with copper and zinc during the recombinant expression of Mg277 is sufficient to restore a fully active holoenzyme. These results demonstrate that the viral enzyme's activation is independent of a chaperone both for disulfide bridge formation and for copper incorporation and suggest that its assembly may not be as regulated as that of its cellular counterparts. A SOD protein is encoded by a variety of DNA viruses but is absent from mimivirus. As in poxviruses, the enzyme might be dispensable when the virus infects Acanthamoeba cells but may allow megavirus chilensis to infect a broad range of eukaryotic hosts. IMPORTANCEMimiviridae are giant viruses encoding more than 1,000 proteins. The virion particles are loaded with proteins used by the virus to resist the vacuole's oxidative stress. The megavirus chilensis virion contains a predicted copper, zinc superoxide dismutase (Cu,Zn-SOD). The corresponding gene is present in some megavirus chilensis relatives but is absent from mimivirus. This first crystallographic structure of a viral Cu,Zn-SOD highlights the features that it has in common with and its differences from cellular SODs. It corresponds to a very stable dimer of the apo form of the enzyme. We demonstrate that upon supplementation of the growth medium with Cu and Zn, the recombinant protein is fully active, suggesting that the virus's SOD activation is independent of a copper chaperone for SOD generally used by eukaryotic SODs. The nucleocytoplasmic large DNA viruses (NCLDV) are a monophyletic group of viruses that infect eukaryotes (1, 2). Mimiviridae are among its largest members, with particle sizes that make them visible by light microscopy and genome complexities overlapping those of the cellular world. They encode proteins thought to be the trademarks of cells, such as elements of the translation machinery as well as original metabolic pathways (3-7). Megavirus chilensis was isolated from an environmental sample from the coast of central Chile by cocultivation with Acantha...

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Cofactor‐Driven Cascade Reactions Enable the Efficient Preparation of Sugar Nucleotides

et al. 2022

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Glycosylation is catalyzed by glycosyltransferases using sugar nucleotides or occasionally lipid‐linked phosphosugars as donors. However, only very few common sugar nucleotides that occur in humans can be obtained readily, while the majority of sugar nucleotides that exist in bacteria, plants, archaea, or viruses cannot be synthesized in sufficient quantities by either enzymatic or chemical synthesis. The limited availability of such rare sugar nucleotides is one of the major obstacles that has greatly hampered progress in glycoscience. Herein we describe a general cofactor‐driven cascade conversion strategy for the efficient synthesis of sugar nucleotides. The described strategy allows the large‐scale preparation of rare sugar nucleotides from common sugars in high yields and without the need for tedious purification processes.

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Giant Virus Megavirus chilensis Encodes the Biosynthetic Pathway for Uncommon Acetamido Sugars

Cited by 24 publications

References 41 publications

The rare sugar N-acetylated viosamine is a major component of Mimivirus fibers

The rare sugar N-acetylated viosamine is a major component of Mimivirus fibers

The Megavirus Chilensis Cu,Zn-Superoxide Dismutase: the First Viral Structure of a Typical Cellular Copper Chaperone-Independent Hyperstable Dimeric Enzyme

Cofactor‐Driven Cascade Reactions Enable the Efficient Preparation of Sugar Nucleotides

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