from John F. Kelly and Ken F. Jarrell writing in Bacterial Glycomics: Current Research, Technology and Applications:
Archaea are single-celled microorganisms that are sufficiently distinct as to constitute a third domain of life. It has been known for some time that Archaea express glycoproteins. However, research to understand the nature of their glycan modifications, the pathways used to produce them as well as their role in archaeal biology has lagged behind similar efforts in Eukarya and Bacteria, at least until recently. Here we describe in some detail the efforts made to determine the composition and structure of archaeal glycan posttranslational modifications and to elucidate their biosynthetic pathways.
Further reading: Bacterial Glycomics: Current Research, Technology and Applications