N-glycosylation in Archaea: on the coordinated actions of Haloferax volcanii AglF and AglM.
Like Eukarya and Bacteria, Archaea are also capable of performing N-glycosylation. In the halophilic archaeon Haloferax volcanii, N-glycosylation is mediated by the products of the agl gene cluster. In the present report, this gene cluster was expanded to include an additional sequence, aglM, shown to participate in the biosynthesis of hexuronic acids contained within a pentasaccharide decorating the S-layer glycoprotein, a reporter H. volcanii glycoprotein. In response to different growth conditions, changes in the transcription profile of aglM mirrored changes in the transcription profiles of aglF, aglG and aglI, genes encoding confirmed participants in the H. volcanii N-glycosylation pathway, thus offering support to the hypothesis that in H. volcanii, N-glycosylation serves an adaptive role. Following purification, biochemical analysis revealed AglM to function as a UDP-glucose dehydrogenase. In a scoupled reaction with AglF, a previously identified glucose-1-phosphate uridyltransferase, UDP-glucuronic acid was generated from glucose-1-phosphate and UTP in a NAD(+)-dependent manner. These experiments thus represent the first step towards in vitro reconstitution of the archaeal N-glycosylation process.
Yurist-Doutsch
Sophie
S
Department of Life Sciences, Ben Gurion University of the Negev, Beersheva 84105, Israel.
Magidovich
Hilla
H
Ventura
Valeria V
VV
Hitchen
Paul G
PG
Dell
Anne
A
Eichler
Jerry
J
D019843:Archaeal Proteins / Q000378:metabolism*; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006031:Glycosylation; D019622:Haloferax volcanii / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005810:Multigene Family; D014158:Transcription, Genetic
D019843:Archaeal Proteins; D006023:Glycoproteins