A large number of O-linked N-acetylglucosamine (O-GlcNAc) residues have been mapped in vertebrate proteins, however targets of O-GlcNAcylation in plants still have not been characterized. We show here that O-GlcNAcylation of the N-terminal region of the capsid protein of Plum pox virus resembles that of animal proteins in introducing O-GlcNAc monomers. Thr-19 and Thr-24 were specifically O-GlcNAcylated. These residues are surrounded by amino acids typical of animal O-GlcNAc acceptor sites, suggesting that the specificity of O-GlcNAc transferases is conserved among plants and animals. In laboratory conditions, mutations preventing O-GlcNAcylation of Thr-19 and Thr-24 did not have noticeable effects on PPV competence to infect Prunus persicae or Nicotiana clevelandii. However, the fact that Thr-19 and Thr-24 are highly conserved among different PPV strains suggests that their O-GlcNAc modification could be relevant for efficient competitiveness in natural conditions.
Bibliographical noteFunding Information:
We thank Elvira Domínguez for technical assistance. This work was supported by Grants BIO2004-02687 from Spanish MEC and SP22-CT-2004 from European Union to J.A.G and the National Science Foundation (MCB-0112826 and -0516690) to N.E.O and by the US Department of Energy (DE-FG02-02ER15353) to N.E.O and L.M.H.
- Capsid protein
- Plum pox virus