The previously discovered posttranslational α-rhamnosylation of a highly conserved arginine residue of elongation factor P was found to be essential for rescue of polyproline stalled ribosomes in clinically relevant species such as Pseudomonas aeruginosa or Neisseria meningitidis, and represents the first example of a rhamnosylated cytosolic protein in bacteria. [1-4] In view of the prevalence and importance of protein glycosylation, we assume that protein rhamnosylation in bacteria might not be limited to EF-P and Arg but represents a more common and so far, overlooked post-translational modification. Highly specific anti rhamnosyl-Asn, rhamnosyl-Ser and rhamnosyl-Thr antibodies are valuable tools to systematically investigate the potential rhamnosyl proteome in bacteria as they allow for the detection of protein mono-rhamnosylation in crude bacterial lysates. [3,5] As a prerequisite for the generation of such antibodies, efficient chemical approaches towards pure and stereochemically well defined α- and β- O- and N-rhamnosyl glycopeptide haptens need to be developed. In this regard, we herein present the synthesis of α- and β-O-rhamnosyl Ser and Thr as well as N-rhamnosyl Asn amino acid building blocks and their incorporation into artificial glycopeptide haptens. The later can be used for the generation of highly specific anti rhamnosyl-Asn, rhamnosyl-Ser and rhamnosyl-Thr antibodies.
- Lassak J.; Keilhauer E.C.; Fürst M.; Wuichet K.; Gödeke J.; Starosta A.L.; Chen J.M.; Sogaard-Andersen L.; Rohr J.; Wilson D.N.; Häussler S.; Mann M.; Jung. K. Arginine-rhamnosylation as new strategy to activate translational elongation factor P. Nat. Chem. Biol. 2015, 11, 266-270.
- Yanagisawa T.; Takahasi H.; Suzuki T.; Masuda A.; Dohmae N.; Yokoyama S. Neisseria meningitidis Translation Elongation Factor P and its Active-Site Arginine Residue Are Essential for Cell Viability. PLoS ONE 2016, 11 (2), e0147907.
- Li X.; Krafczyk R.; Macošek J.; Li Y. L.; Zou Y.; Simon B.; Pan X.; Wu Q. Y.; Yan F.; Li S.; Hennig J.; Jung K.; Lassak J.; Hu H.G. Resolving the α-glycosidic linkage of arginine-rhamnosylated translation elongation factor P triggers generation of the first ArgRha specific antibody. Chem. Sci. 2016, 7, 6995-7001.
- Wang S.; Corcilius L.; Sharp P. P.; Rajkovic A.; Ibba M.; Parker B. L.; Payne R. J. Synthesis of rhamnosylated arginine glycopeptides and determination of the glycosidic linkage in bacterial elongation factor P. Chem. Sci. 2017, 8, 2296-2302.
- Krafczyk R., Macošek J., Jagtap P. K. A.; Gast D.; Wunder S.; Mitra P.; Jha A. K.; Rohr J.; Hoffmann-Röder A.; Jung K.; Hennig J.; Lassak J. Structural basis for EarP-mediated arginine glycosylation of translation elongation factor EF-P. mBio 2017, 8 (5), e01412-17.