title: Glycosides of hydroxyproline: some recent, unusual discoveries.
abstract: Glycosides of hydroxyproline (Hyp) in the plant cell wall matrix were discovered by Lamport and co-workers in the 1960s. Since then, much has been learned about these Hyp-rich glycoproteins. The intent of this review was to compare and contrast some less common structural motifs, in nontraditional roles, to uncover themes. Arabinosylation of short-peptide plant hormones is essential for growth, cell differentiation and defense. In a very recent development, prolyl hydroxylase and arabinosyltransferase activity has been shown to have a direct impact on the growth of root hairs in Arabidopsis thaliana. Pollen allergens of mugwort and ragweed contain proline-rich domains that are hydroxylated and glycosylated and play a structural role. In the case of mugwort, this domain also presents a significant immunogenic epitope. Major crops, including tobacco and maize, have been used to express and produce recombinant proteins of mammalian origin. The risks of plant-imposed glycosylation are discussed. In unicellular eukaryotes, Skp1 (a subunit of the E3(SCF) ubiquitin ligase complex) harbors a key Hyp residue that is modified by a linear pentasaccharide. These modifications may be involved in sensing oxygen levels. A few studies have probed the impact of glycosylation on the structure of Hyp-containing peptides. These have necessarily looked at small, synthetic molecules, since natural peptides and proteins are often isolable in only minuscule amounts and/or are heterogeneous in nature. The characterization of native structural motifs, together with the determination of glycopeptide conformation and properties, holds the key to rationalizing nature's architectural design.
authors.affiliation: Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA. cmtaylor@lsu.edu
authors.forename: Carol M
authors.initials: CM
authors.lastname: Taylor
authors.forename: Chamini V
authors.initials: CV
authors.lastname: Karunaratne
authors.forename: Ning
authors.initials: N
authors.lastname: Xie
mesh_terms: D000818:Animals; D006020:Glycopeptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006027:Glycosides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D006909:Hydroxyproline / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D006020:Glycopeptides; D006027:Glycosides; D006909:Hydroxyproline